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Article

Combined Toxicity of Cannabidiol Oil with Three Bio-Pesticides against Adults of Sitophilus Zeamais, Rhyzopertha Dominica, Prostephanus Truncatus and Trogoderma Granarium

by
Spiridon Mantzoukas
1,*,
Nikolaos Kalyvas
1,
Aristeidis Ntoukas
1,
Ioannis Lagogiannis
1,
Konstantinos Farsalinos
1,
Panagiotis A. Eliopoulos
2 and
Konstantinos Poulas
1,*
1
Department of Pharmacy, University of Patras, 26504 Patras, Greece
2
Department of Agrotechnology, University of Thessaly, Gaiopolis, 41500 Larissa, Greece
*
Authors to whom correspondence should be addressed.
Int. J. Environ. Res. Public Health 2020, 17(18), 6664; https://doi.org/10.3390/ijerph17186664
Submission received: 1 July 2020 / Revised: 10 September 2020 / Accepted: 11 September 2020 / Published: 13 September 2020
(This article belongs to the Special Issue Current Status, Challenges, and Prospects of Biopesticides)
Versions Notes

Abstract

:
The present study investigates the interaction between cannabidiol (CBD) oil and three biopesticides: Azatin and two baculovirus formulations (Madex and Helicovex), both separately and in combination, in order to investigate their interaction against adults of four major coleopteran stored-product pests: Sitophilus zeamais (Coleoptera: Curculionidae), Rhyzopertha dominica (Coleoptera: Bostrichidae), Prostephanus truncatus (Coleoptera: Bostrichidae) and Trogoderma granarium (Coleoptera: Dermestidae). CBD, which has been understudied for its insecticidal properties, was applied at three different doses (500, 1500 and 3000 ppm). The biopesticides were administered at 1500 ppm. Interactions in the combined treatments were mathematically estimated as not synergistic and mostly competitive except for the combined treatments of CBD (1500 and 3000 ppm) with Azatin (1500 ppm) which were marked by an additive interaction. In its individual application, CBD oil generated the highest insect mortality while its effect was clearly dose-dependent. The findings reveal a promising effect of CBD oil against these coleopterans which had not been previously tested together.

1. Introduction

Insect pests cause severe damage to plant life and crops with an estimation of approximately 30% of crop yields lost due to pathogens [1], rendering their control a crucial issue for farmers worldwide. Although chemical pesticides remain the most effective method for the management of serious storage pests, their action has proven to be hazardous for the user and the environment [2,3]. Moreover, their extensive and often unnecessary application has increased resistance to chemical pesticides in target species [4]. Appreciation for the health and environmental risks involved in the use of chemical pesticides has propelled a shift towards the search for biopesticides as well as botanicals with insecticidal and repellent effects. Botanical insecticides present an array of advantages including low mammalian toxicity, environmental safety, efficacy as well as a reduced likelihood to cause resistance in arthropods [5,6,7], and as such, they have legitimately attracted a high degree of interest for their pest control potential, including in the management of stored-product pests [8].
The use of entomopathogenic microorganisms is central in biological pest control [9,10,11,12,13,14]. Entomopathogenic viruses are among the microorganisms whose value has been acknowledged in biological pest control as they exhibit good insecticidal potential, high selectivity, making them safe for nontarget arthropods, and compatible with other pest control methods [15]. Cydia pomonella Granulovirus (CpGV) and Helicoverpa armigera Nucleopolyhedrovirus (HearNPV) are two baculoviruses with proven efficacy against Lepidopteran pests. Research has shown that HearNPV can be utilized as a control agent for pests which attack chickpea and sunflower crops [16,17]. Likewise, many plants can be used as biopesticides, as many plant species are famous for their insecticidal properties [18,19,20,21]. A widely used plant species is Azadirachta indica A. Juss (Sapindales: Meliaceae). Numerous studies highlight the unique properties of its extracted oil and its effectiveness as an insecticide [22,23,24]. Research has also been conducted over recent years on Cannabis sativa L. (Rosids: Cannabaceae) and, especially, one major cannabinoid that is present in the plant which is cannabidiol (CBD). Cannabis-based insecticides and repellents are widely available [5,25]; however, the mode of action of CBD as an insecticide or repellent is still under investigation.
Two or more biopesticides are often combined to create an enhanced product with a better efficiency or duration [26,27,28]. However, they may not coexist harmoniously in a mixture and their action is not always additive. Their interaction can be synergistic or antagonistic [29,30,31,32,33,34,35], depending on the concentration, species, mode of action, target organism, temperature conditions, and relative humidity (r.h) conditions of each biopesticide [33,34,35,36,37,38,39,40,41,42,43,44,45,46,47]. The combined use of two or more biopesticides in one mixture may result in less (or more) environmental harm or less (or more) harm to nontarget organisms [48,49,50]. Biopesticides based on plant essential oils and microorganisms are considered relatively safe and their efficacy has been demonstrated against different insect species.
The aim of the present study was to investigate the insecticidal effect of CBD oil in combination with three biopesticides: CBD + Madex (Cydia Pomonella Granulovirus (CpGV)), CBD + Azatin (Azadirachtin), and CBD + Helicovex (Helicoverpa Armigera Nucleopoyhedrovirus (HearNPV)). The above combinations were tested against adults of Sitophilus zeamais (Coleoptera: Curculionidae), Rhyzopertha dominica (Coleoptera: Bostrichidae), Prostephanus truncatus (Coleoptera: Bostrichidae), and Trogoderma granarium (Coleoptera: Dermestidae). This study is a follow up on previous similar studies investigating the synergism between biopesticides, and biopesticides and botanicals to enhance toxicity against stored-product pests [26,27,28]. CBD oil and these three biopesticides have never been investigated for their combined action against the four coleopteran pests. This is the first time CBD oil has been tested against the specific coleopteran pests.

2. Materials and Methods

2.1. Insect Rearing

Four major stored-product beetle species were selected: the maize weevil S. zeamais, the lesser grain borer R. dominica, the larger grain borer P. truncatus and the khapra beetle, T. granarium. These species cover a wide spectrum of globally distributed stored-product pests and cause serious losses and degradations to a wide range of commodities. All species were reared in a growth chamber (PHC Europe/Sanyo/Panasonic Biomedical MLR-352-PE) in controlled environmental conditions, at 27.5 °C and 75% relative humidity (r.h.) in the Laboratory of Molecular Biology and Immunology, Department of Pharmacy, University of Patras. We used mixed sex adults, <2 weeks old. The bioassays were carried out on wheat (var. Mexa). This grain was adjusted at 12% moisture content (m.c.), via storage in ambient conditions, for 28 d. Whole grain kernels were used because these species are known to infest sound grains.

2.2. Bioassay

Individual lots of 500 g of wheat were placed in 0.45 L cylindrical glass jars, in the laminar flow cabinet (Equip Vertical Air Laminar Flow Cabinet Clean Bench. Mechanical Application LTD. Athens. Greece). The CBD solution (3% oil produced by Enecta Athens, Greece) was diluted with methanol (MeOH) and was applied on the commodities at three concentrations (500, 1500 and 3000 ppm). The same process was followed for the biopesticides whereby Madex (Cydia pomonella Granulovirus (CpGV)) (Hellafarm, Athens, Greece), Azatin (Azadirachtin A 2.6 EC) (K&NE Earth Matters, Thessaloniki, Greece), and Helicovex (Helicoverpa αrmigera Nucleopoyhedrovirus (HearNPV)) (Hellafarm, Athens, Greece) were tested at 1500 ppm. Solutions were sprayed on the products using the Potter spray tower (Burkard Manufacturing Co. Ltd., Rickmansworth, Hertfordshire, U.K.) at 1 kgf cm−2. The entire process was repeated twenty times, whereby new groups of insects were prepared each time. After the solutions had been sprayed on the product, the wheat lots were placed back into the jars and were shaken manually for 30 s to achieve an equal distribution of the treatment. The product was then air dried for 30 min especially for the CBD oil concentrations because methanol evaporates within a short time. Separate lots of wheat were sprayed with distilled water and MeOH, to serve as controls. From each jar, ten 20 g samples were taken and placed in cylindrical plastic vials (3 cm in diameter, 8 cm in height). The vials had a plastic lid with a hole in the center covered with fine mesh, while the internal “neck” of the vials was covered with Fluon (Northern Products, Woonsocket, RI USA), to prevent adult insects from escaping. Twenty individuals were placed within each vial (separate vials for each species) and the vials were placed in plastic boxes with saturated solutions of sodium chloride to maintain 75% r.h. Two hundred coleopteran adults were used for each concentration (20 adults per replication) and the experiment was replicated ten times. All boxes were then placed in incubators set at 27.5 °C and 75% r.h. Adults were observed daily, and mortality was recorded at 7, 14, 21 and 28 days after treatment.
To study the combined effect of the treatments, adult insects were treated with a combination of each biopesticide with a CBD oil suspension, resulting in nine different combinations (Azatin 1500 ppm + CBD 500 ppm, Azatin 1500 ppm + CBD 1500 ppm, Azatin 1500 ppm + CBD 3000 ppm; Madex 1500 ppm + CBD 500 ppm, Madex 1500 ppm + CBD 1500 ppm, Madex 1500 ppm + CBD 3000 ppm; Helicovex 1500 ppm + CBD 500 ppm, Helicovex 1500 ppm + CBD 1500 ppm, Helicovex 1500 ppm + CBD 3000 ppm). The product was initially sprayed with 2 mL of the CBD oil and, after 2 s, with 2 mL of the biopesticide concentration. Twenty individuals were placed within each vial (separate vials for each species), and the vials were placed in plastic boxes with saturated solutions of sodium chloride to maintain 75% r.h. Replications and spray procedures for the combined treatments were carried out as in the individual treatments. Adults were observed daily, and mortality was recorded at 7, 14, 21 and 28 days after treatment.

2.3. Mathematical Estimation

The interaction between the pathogens was estimated using the formula of Robertson and Preisler [51]:
PE = P0 + (1 − P0) × (P1) + (1 − P0) × (1 − P1) × (P2)
where PE is the expected mortality induced by the combination of the two pathogens; P0 is the observed mortality of the control; P1 is the observed mortality caused by the first pathogen (separate action); P2 is the observed mortality caused by the second pathogen (separate action). The distribution was determined by the chi-square formula:
x2 = (L0 − LE)2/LE + (D0 − DE)2/DE
where L0 is the number of recorded live larvae of the control. D0 is the number of recorded dead larvae of the control, LE is the expected number of live larvae, and DE is the expected number of dead larvae (estimated the same as PE, with Equation (1)). The formula was used to test the hypothesis independent–simultaneous relationship (df = 1, p = 0.05). If x2 < 3.84, the ratio is defined as additive, if x2 > 3.84 and the observed mortality is higher than expected, the relationship is defined as synergistic. On the contrary, if x2 > 3.84 and the observed mortality is less than expected, the relationship is defined as competitive.

2.4. Statistical Analysis

All values were arcsine transformed prior to the analysis to reduce the effect of the variance. Data were analyzed by a two-way ANOVA using the general linear model of the SPSS (version 25) (IBM 2019, Armonk, NY, USA). In case of significant F values, means were compared using the Bonferroni test. The Kaplan–Meier method of the SPSS (ver. 25) was also selected to determine the mean survival time of S. zeamais, R. dominica, P. truncatus and T. granarium adults following the application of the treatments. The Cox regression of the SPSS (ver. 25), a common survival analysis regression method that describes the relation between the event incidence and a set of covariates, was selected to determine the hazard effect of the individual and combined treatments.

3. Results

Essential oil and biopesticides induced significantly different levels of mortality on adults of S. zeamais, R. dominica, P. truncatus and T. granarium. Significant differences were recorded between treatment (F = 108.272, df = 6.139, p < 0.001) and replication (F = 10.909, df = 4.139, p < 0.001) but not between the coleopteran species of the experiment (F = 1.911, df = 3.139, p = 0.132) as factors, in relation to the dependent variable of mortality at 28 days. The two-way factor model of coleopteran species × treatment (F = 0.9722, df = 18.139, p = 0.001) and treatment × replication (F = 4.950, df = 24.139, p = 0.001) showed a significant effect in terms of the mortality of coleopteran adults at 28 days. The mean beetle mortality caused by the separate action of CBD Oil, Azatin, Helicovex and Madex is presented in Table 1. More specifically, 28 days after the treatment with CBD oil, the mortality of S. zeamais adults increased from 38% (500 ppm) to 70% (3000 ppm), of R. dominica from 44% (500 ppm) to 84% (3000 ppm), of P. truncatus from 48% (500 ppm) to 80% (3000 ppm), and of T. granarium from 48% (500 ppm) to 62% (3000 ppm) (Table 1). At 28 days, Azatin-induced mortality to Coleoptera was between 38% (T. granarium) and 50% (P. truncatus); Helicovex-induced mortality was between 16% (S. zeamais) and 20% (all others) (Table 1); Madex-induced mortality was between 18% (S. zeamais) and 22% (R. dominica) (Table 1).
A total of nine combined treatments of CBD oil with the biopesticides were applied against S. zeamais. R. dominica. P. truncatus and T. granarium. Significant differences were recorded between treatment (F = 57.641, df = 8.179, p < 0.001) and between the tested insects of the experiment (F = 14.149, df = 3.179, p < 0.001) as factors, in relation to the dependent variable of mortality, at 28 days. The adult mortality of the four beetles varied significantly in terms of the combinations at two-way factor insect * treatment (F = 2.138, df = 24. 179, p = 0.003) at 28 days. After 28 days, the mean mortality of the combined treatments of CBD Oil, Azatin, Helicovex and Madex was, for S. zeamais adults treated with CBD and Azatin between 36% (CBD 500–Azatin 1500 ppm) and 84% (CBD 3000–Azatin 1500 ppm), with CBD and Helicovex between 30% (CBD 500–Helicovex 1500 ppm) and 62% (CBD 3000–Helicovex 1500 ppm), and with CBD and Madex between 18% (CBD 500–Madex 1500 ppm) and 40% (CBD 3000–Madex 1500 ppm) (Table 2); for R. dominica adults treated with CBD and Azatin, the mean mortality was between 50% (CBD 500–Azatin 1500 ppm) and 90% (CBD 3000–Azatin 1500 ppm), with CBD and Helicovex between 40% (CBD 500–Helicovex 1500 ppm) and 70% (CBD 3000–Helicovex 1500 ppm), and with CBD and Madex between 32% (CBD 500–Madex 1500 ppm) and 62% (CBD 3000–Madex 1500 ppm) (Table 2); for P. truncatus adults treated with CBD and Azatin, the mean mortality was between 44% (CBD 500–Azatin 1500 ppm) and 94% (CBD 3000–Azatin 1500 ppm), with CBD and Helicovex between 38% (CBD 500–Helicovex 1500 ppm) and 70% (CBD 3000–Helicovex 1500 ppm), and with CBD and Madex between 26% (CBD 500–Madex 1500 ppm) and 52% (CBD 3000–Madex 1500 ppm) (Table 2); for T. granarium adults treated with CBD and Azatin, the mean mortality was between 50% (CBD 500–Azatin 1500 ppm) and 62% (CBD 3000–Azatin 1500 ppm), with CBD and Helicovex between 46% (CBD 500–Helicovex 1500 ppm) and 68% (CBD 3000–Helicovex 1500 ppm), and with CBD and Madex between 38% (CBD 500–Madex 1500 ppm) and 54% (CBD 3000–Madex 1500 ppm) (Table 2).
The results of the combined treatments showed different types of interaction between the biopesticides and CBD oil. In the cases of S. zeamais, the interaction between the treatments was competitive except for one (Table 3). For P. truncatus, the interaction between the treatments was competitive except two, and for R dominica, the interaction between the treatments was competitive except three (Table 3). An additive interaction was recorded for the combined treatments of the CBD oil (1500 and 3000 ppm) with Azatin (1500 ppm) for all above beetles (Table 3). By contrast, Helicovex and CBD oil marked an additive interaction against T. granarium at all three doses, and against R. dominica at one dose (Table 3). No synergistic relationship was recorded in any of the combinations (Table 3).
The six combined treatments which were overall toxic to S. zeamais, R. dominica, P. truncatus and T. granarium adults had positive β-values (Table 4). The combined treatments which exhibited a dose-dependent action were CBD 3000–Madex 1500 ppm, CBD 1500–Helicovex 1500 ppm, CBD 3000–Helicovex 1500 ppm, CBD 500–Azatin 1500 ppm, CBD 1500–Azatin 1500 ppm, and CBD 3000–Azatin 1500 ppm. The overall Hazard Rate (Exp (B)) for all combined treatments was higher than the control. Finally, the above treatments were not statistically significant, except for CBD 3000–Helicovex 1500 ppm, CBD 1500–Azatin 1500 ppm and CBD 3000–Azatin 1500 ppm with p values of <0.001, <0.001 and <0.001, respectively (Table 4). The individual treatments which also had an effect on the overall mortality of S. zeamais, R dominica, P. truncatus and T. granarium adults had positive β-values and included all three CBD oil concentrations; they were also statistically significant from the remaining individual treatments. The overall hazard rate (Exp (B)) for the CBD oil concentrations was higher than the control.

4. Discussion

The present study represents an investigation of the individual and combined insecticidal effect of CBD oil and three biopesticides, Azatin, Madex and Helicovex. In our study, the combined treatments of CBD with the biopesticides produced varying results. Our hypothesis was that the interaction between treatments would be more additive than synergistic. Insects would thus die from a reinforced action. Our results support this hypothesis in the case of CBD with Azatin for all tested insects, as well as in the case of two insects with CBD and Helicovex. Overall, no combination exhibited synergism.
On its own, CBD oil yielded the highest mortality rates at 28 days. Its action was dose-dependent which is generally the case with essential oils, whose effects include metabolic and physiological disruptions, neurotoxic effects, and histological changes [29]. Benelli et al. [5] report that the essential oil from the inflorescence of industrial hemp was highly toxic to aphids and flies, although results ranged from moderate to scarcely toxicity larvae and adults. C. sativa L and CBD-related studies on their insecticidal properties are scarce. In most studies, C. sativa was tested as a companion plant, harvested plant material, in aqueous and solvent extracts, and as essential oil [25]. There is bound to be variation in the findings concerning the insecticidal effects of the plant. In their review, McPartland and Sheikh [25] concluded that of all bioassays, the essential oil produced the best results in the treated insects which were mainly thin-cuticle small arthropods.
Azadin (1500 ppm) generated moderate to low mortality reaching a peak at 50% (P. truncatus) [30]. Similarly, albeit as a crude powder, A. indica was tested against P. truncatus and was found to be weakly toxic to the insect, causing a mere mortality of 40% at 28 days [30]. In a similar vein, azadirachtin-enriched neem kernel extracts on wheat consumed by R. dominica did not have any effect on parent mortality although they inhibited F1 progeny by 98% [47]. Tofel et al. [48] found Azadirachtin seed oil to be lethal to Callosobruschus maculatus Fabricius (Coleoptera: Chrysomelidae) and S. zeamais adults. Variation in the effect of azadirachtin and neem extracts may be the product of differences in the derivatives and formulations used as well as of a complex of several other factors such as grain type, target species, dosage, temperature, humidity and others [49]. In the present study, moderate to low mortality could be interpreted as an indirect event resulting from the disruption in the feeding of the insect, drawing on Xie et al. [51] in their interpretation of the killing of Sitophilus oryzae Linnaeus (Coleoptera: Curculionidae), Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) and Cryptolestes ferrugineus Ganglbauer (Coleoptera: Laemophloeidae).
Finally, Madex and Helicovex were ineffective as mortality rates did not exceed 22% at 28 days. The low mortality can be accounted for by the age of the insects, as viruses are mostly pathogenic to larvae whereby molting and pupation is blocked by the infection [52], and by the different insect order as the two baculoviruses are mostly effective against Lepidopterans. Moreover, they were slow in their action, which is a known disadvantage of viruses in general [53].
Examining how pesticides interact with each other advances research on to the creation of more effective, cost efficient and lasting pesticidal products. Interaction is determined by the interplay of many factors such as the compound itself, dose, insect species, and others. One or all individual components of a combination may enhance (synergism) or suppress (antagonism/competition) each other’s toxicity, or simply remain within the additive framework [54,55,56,57]. The observed additive effect with high toxicity values (B and Exp (B)) is the result of the Azadirachtin making insects more sensitive to CBD, thus adding to the result.
It is also worth pointing out that T. granarium (all concentrations) and R. dominica (CBD 1500–Helicovex 1500 ppm) were the only beetles in which CBD and the Helicovex did not compete, whereas CBD had a negative interaction with Madex or Helicovex in the case of the other two Coleoptera. Thus, an additive effect with very good toxicity values (B and Exp (B)) was shown when adults of T. granarium and R. dominica were treated with combined concentrations. The T. granarium and R. dominica cases are a finding worth exploring further.
On the contrary, the mathematical estimation revealed that most combinations were competitive. A competitive interaction refers to the negative relationship between pathogens. The nature of competition between tested treatments is not documented. In our case, the combined use of CBD with Madex exhibited negative B values but good toxicity values. The combined concentration of CBD with Madex did not produce increased hazard and decreased survival time in terms of the mortality of the beetles.

5. Conclusions

Although acute toxicity of plant-derived substances is lower than that of their chemical counterparts, they have attracted a high degree of interest for their pest control potential, including for the management of stored-product pests. As research in biological control is gaining considerable momentum, and as the list of entomopathogenic properties of plants and biopesticides is continually enriched, our findings highlight the potential of CBD against major stored-product pests and add to the limited literature concerning this essential oil.

Author Contributions

Conceptualization, S.M. and K.P.; methodology, S.M.; software, S.M.; validation, S.M., P.A.E., I.L., and K.P.; formal analysis, S.M., I.L., and A.N.; investigation, S.M., N.K., I.L., and A.N.; resources, K.P.; data curation, S.M.; writing—original draft preparation, S.M., A.N., K.F., P.A.E., and K.P.; writing—review and editing, S.M., P.A.E. and K.P.; visualization, S.M.; supervision, K.P.; project administration, K.P.; funding acquisition, K.P. All authors have read and agreed to the published version of the manuscript.

Funding

We acknowledge support of this work by the project “Synthetic Biology: From omics technologies to genomic engineering (OMIC-ENGINE)” (MIS 5002636), which is implemented under the Action “Reinforcement of the Research and Innovation Infrastructure”, funded by the Operational Programme “Competitiveness, Entrepreneurship and Innovation” (NSRF 2014–2020) and co-financed by Greece and the European Union (European Regional Development Fund).

Acknowledgments

We would like to thank Ioanna Zampara in interpreting and translating, for her help with the language. Authors are also grateful to the National Research Infrastructure Program of the University of Patras “OMIC-ENGINE-Synthetic Biology: from omics technologies to genomic engineering” for financial support of the personnel.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Becker-Ritt, A.B.; Carlini, C.R. Fungitoxic and insecticidal plant polypeptides. Biopolymers 2012, 98, 367–384. [Google Scholar] [CrossRef] [PubMed]
  2. Diaz, J.H. Chemical and plant-based insect repellents: Efficacy, safety, and toxicity. Wilderness Environ. Med. 2016, 27, 153–163. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  3. Jiang, W.; Hernandez, B.; Richmond, D.; Yanga, N. Harvesters in strawberry fields: A literature review of pesticide exposure, an observation of their work activities, and a model for exposure prediction. J. Expo. Sci. Environ. Epidemiol. 2017, 27, 391–397. [Google Scholar] [CrossRef] [PubMed]
  4. Collins, P.J.; Schlipalius, D.I. Insecticide resistance. In Recent Advances in Stored Product Protection; Athanassiou, C.G., Arthur, F.H., Eds.; Springer: Berlin/Heidelberg, Germany, 2018; pp. 169–182. [Google Scholar]
  5. Benelli, G.; Pavela, R.; Petrelli, R.; Cappellaci, L.; Santini, G.; Fiorini, D.; Sut, S.; Dall’Acqua, S.; Canale, A.; Maggi, F. The essential oil from industrial hemp (Cannabis sativa L.) by-products as an effective tool for insect pest management in organic crops. Ind. Crop. Prod. 2018, 122, 308–315. [Google Scholar] [CrossRef]
  6. Pavela, R.; Benelli, G. Essential oils as eco-friendly biopesticides? Challenges and consraints. Trends Plant Sci. 2016, 21, 1000–1007. [Google Scholar] [CrossRef] [PubMed]
  7. Said, P.; Pashte, V. Botanicals: The protectants of stored grains pests. Biosci. Trends 2015, 8, 3750–3755. [Google Scholar]
  8. Spochacz, M.; Chowański, S.; Walkowiak-Nowicka, K.; Szymczak, M.; Adamski, Z. Plant-derived substances used against beetles–pests of stored crops and food–and their mode of action: A review. Compr. Rev. Food Sci. Food Saf. 2018, 17, 1339–1366. [Google Scholar] [CrossRef] [Green Version]
  9. Kumar, K.K.; Sridhar, J.; Murali-Baskaran, R.K.; Senthil-Nathan, S.; Kaushal, P.; Dara, S.K.; Arthurs, S. Microbial biopesticides for insect pest management in India: Current status and future prospects. J. Invertebr. Pathol. 2019, 165, 74–81. [Google Scholar] [CrossRef]
  10. Hatting, J.L.; Moore, S.D.; Malan, A.P. Microbial control of phytophagous invertebrate pests in South Africa: Current status and future prospects. J. Invertebr. Pathol. 2019, 165, 54–66. [Google Scholar] [CrossRef]
  11. Lovett, B.; St. Leger, R.J. Genetically engineering better fungal biopesticides. Pest Manag. Sci. 2018, 74, 781–789. [Google Scholar] [CrossRef]
  12. Beck, J.J.; Vannette, R.L. Harnessing insect-microbe chemical communications to control insect pests of agricultural systems. J. Agric. Food Chem. 2017, 65, 23–28. [Google Scholar] [CrossRef] [PubMed]
  13. Carpio, C.; Dangles, O.; Dupas, S.; Léry, X.; López-Ferber, M.; Orbe, K.; Páez, D.; Rebaudo, F.; Santillán, A.; Yangari, B.; et al. Development of a viral biopesticide for the control of the Guatemala potato tuber moth Tecia solanivora. J. Invertebr. Pathol. 2013, 112, 184–191. [Google Scholar] [CrossRef] [PubMed]
  14. Arthurs, S.; Dara, S.K. Microbial biopesticides for invertebrate pests and their markets in the United States. J. Invertebr. Pathol. 2019, 165, 13–21. [Google Scholar] [CrossRef] [PubMed]
  15. Raymond, B.; Sayyed, A.H.; Wright, D.J. The compatibility of a nucleopolyhedrosis virus control with resistance management for Bacillus thuringiensis: Co-infection and cross-resistance studies with the diamondback moth, Plutella xylostella. J. Invertebr. Pathol. 2006, 93, 114–120. [Google Scholar] [CrossRef] [PubMed]
  16. Jaques, R.P.; Hardman, J.M.; Laing, J.E.; Smith, R.E.; Bent, E. Orchard trials in Canada on control of Cydia Pomonella (Lep: Tortricidae) by granulosis Virus. Entomophaga 1994, 39, 281–292. [Google Scholar] [CrossRef]
  17. Sun, X. History and current status of development and use of viral insecticides in China. Viruses 2015, 7, 306–319. [Google Scholar] [CrossRef]
  18. Rajashekar, Y.; Bakthavatsalam, N.; Shivanandappa, T. Botanicals as grain protectants. Psyche 2012, 2012, 646740. [Google Scholar] [CrossRef]
  19. Omar, K.; Faraj, N.M.; Malik, S.A.A.; Al-Farhani, I.M. Effect of some medicinal plants extracts and cypermthrin against Khapra Beetle (Trogoderma granarium Everts). Emir. J. Food Agric. 2012, 24, 120–127. [Google Scholar]
  20. Maia, M.F.; Moore, S.J. Plant-based insect repellents: A review of their efficacy, development, and testing. Malar. J. 2011, 10 (Suppl. 1), S11. [Google Scholar] [CrossRef] [Green Version]
  21. Athanassiou, C.G.; Kavallieratos, N.G.; Evergetis, E.; Katsoula, A.-M.; Haroutounian, S.A. Insecticidal Efficacy of Silica Gel with Juniperus oxycedrus ssp. oxycedrus (Pinales: Cupressaceae) Essential Oil Against Sitophilus oryzae (Coleoptera: Curculionidae) and Tribolium confusum (Coleoptera: Tenebrionidae). J. Econ. Entomol. 2013, 106, 1902–1910. [Google Scholar] [CrossRef]
  22. Gupta, S.C.; Prasad, S.; Tyagi, A.K.; Kunnumakkara, A.B.; Aggarwal, B.B. Neem (Azadirachta indica): An indian traditional panacea with modern molecular basis. Phytomedicine 2017, 34, 14–20. [Google Scholar] [CrossRef] [PubMed]
  23. Benelli, G.; Canale, A.; Toniolo, C.; Higuchi, A.; Murugan, K.; Pavela, R.; Nicoletti, M. Neem (Azadirachta indica): Towards the ideal insecticide? Nat. Prod. Res. 2017, 31, 369–386. [Google Scholar] [CrossRef] [PubMed]
  24. Pascoli, M.; Jacques, M.T.; Agarrayua, D.A.; Avila, D.S.; Lima, R.; Fraceto, L.F. Neem oil based nanopesticide as an environmentally-friendly formulation for applications in sustainable agriculture: An ecotoxicological perspective. Sci. Total Environ. 2019, 677, 57–67. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  25. McPartland, J.M.; Sheikh, Z. A Review of Cannabis sativa-Based Insecticides, Miticides, and Repellents. J. Entomol. Zool. Stud. 2018, 6, 1288–1299. Available online: https://www.cabdirect.org (accessed on 6 July 2020).
  26. Mascarin, G.M.; Delalibera, I. Insecticidal activity of the granulosis virus in combination with neem products and talc powder against the potato tuberworm Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae). Neotrop. Entomol. 2012, 41, 223–231. [Google Scholar] [CrossRef] [Green Version]
  27. Awan, D.A.; Ahmad, F.; Saleem, M.A.; Shakoori, A.R. Synergistic effect of piperonyl butoxide and emamectin benzoate on enzymatic activities in resistant populations of red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae). Environ. Sci. Pollut. Res. 2019, 26, 14200–14213. [Google Scholar] [CrossRef]
  28. Mwila, K.; Burton, M.H.; Van Dyk, J.S.; Pletschke, B.I. The effect of mixtures of organophosphate and carbamate pesticides on acetylcholinesterase and application of chemometrics to identify pesticides in mixtures. Environ. Monit. Assess. 2013, 185, 2315–2327. [Google Scholar] [CrossRef]
  29. Campolo, O.; Giunti, G.; Russo, A.; Palmeri, V.; Zappalà, L. Essential oils in stored product insect pest control. J. Food Qual. 2018, 2018, 6906105. [Google Scholar] [CrossRef] [Green Version]
  30. Chebet, F.; Deng, A.; Ogendo, J.O.; Kamau, A.; Bett, P. Bioactivity of selected plant powders against Prostephanus truncatus (Coleoptera: Bostrichidae) in stored maize grains. Plant Prot. Sci. 2013, 49, 34–43. [Google Scholar] [CrossRef] [Green Version]
  31. Faraone, N.; Hillier, N.K.; Cutler, G.C. Plant essential oils synergize and antagonize toxicity of diferent conventional insecticides against Myzus persicae (Hemiptera: Aphididae). PLoS ONE 2015, 10, e0127774. [Google Scholar] [CrossRef]
  32. Benelli, G.; Pavela, R.; Iannarelli, R.; Petrelli, R.; Cappellacci, L.; Cianfaglione, K.; Afshar, F.H.; Nicoletti, M.; Canale, A.; Maggi, F. Synergized mixtures of Apiaceae essential oils and related plant-borne compounds: Larvicidal effectiveness on the flariasis vector Culex quinquefasciatus Say. Ind. Crop. Prod. 2017, 96, 186–195. [Google Scholar] [CrossRef]
  33. Mantzoukas, S.; Milonas, P.; Kontodimas, D.; Angelopoulos, K. Interaction between the entomopathogenic bacterium Bacillus thuringiensis subsp. kurstaki and two entomopathogenic fungi in bio-control of Sesamia nonagrioides (Lefebvre) (Lepidoptera: Noctuidae). Ann. Microbiol. 2013, 63, 1083–1091. [Google Scholar] [CrossRef]
  34. Mantzoukas, S.; Zikou, A.; Triantafillou, V.; Lagogiannis, I.; Eliopoulos, P.A. Ιnteractions between Beauveria bassiana and Isaria fumosorosea and their hosts Sitophilus granarius (L.) and Sitophilus oryzae (L.) (Coleoptera: Curculionidae). Insects 2019, 10, 362. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  35. Mantzoukas, S. The effect of Metarhizium robertsii and Bacillus thuringiensis against Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). Adv. Ecol. Environ. Res. 2019, 136–146. Available online: https://www.ss-pub.org/aeer/the-effect-of-metarhizium-robertsii-and-bacillus-thuringiensis-against-helicoverpa-armigera-hubner-lepidoptera-noctuidae/ (accessed on 12 September 2020).
  36. Shapiro-Ilan, D.I.; Cottrell, T.E.; Bock, C.; Mai, K.; Boykin, D.; Wells, L.; Hudson, W.G.; Mizell, R.F., 3rd. Control of pecan weevil with microbial biopesticides. Environ. Entomol. 2017, 46, 1299–1304. [Google Scholar] [CrossRef]
  37. Peng, D.; Luo, K.; Jiang, H.; Deng, Y.; Bai1, L.; Zhou, X. Combined use of Bacillus subtilis strain B-001 and bactericide for the control of tomato bacterial wilt. Pest Manag. Sci. 2017, 73, 1253–1257. [Google Scholar] [CrossRef] [PubMed]
  38. Dakhel, W.H.; Latchininsky, A.V.; Jaronski, S.T. Efficacy of two entomopathogenic fungi, Metarhizium brunneum, strain F52 alone and combined with Paranosema locustae against the migratory grasshopper, Melanoplus sanguinipes, under laboratory and greenhouse conditions. Insects 2019, 10, 94. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  39. Xu, X.M.; Jeffries, P.; Pautasso, M.; Jeger, M.J. Combined use of biocontrol agents to manage plant diseases in theory and practice. Phytopathology 2011, 101, 1024–1031. [Google Scholar] [CrossRef] [Green Version]
  40. Xu, X.M.; Jeger, M.J. Theoretical modeling suggests that synergy may result from combined use of two biocontrol agents for controlling foliar pathogens under spatial heterogeneous conditions. Phytopathology 2013, 103, 768–775. [Google Scholar] [CrossRef] [Green Version]
  41. Portman, S.L.; Krishnankutty, S.M.; Reddy, G.V.P. Entomopathogenic nematodes combined with adjuvants presents a new potential biological control method for managing the wheat stem sawfly, cephus cinctus (Hymenoptera: Cephidae). PLoS ONE 2016, 11, e0169022. [Google Scholar] [CrossRef]
  42. Nathan, S.S.; Kalaivani, K.; Murugan, K. Effect of biopesticides on the lactate dehydrogenase (LDH) of the rice leaffolder, Cnaphalocrocis medinalis (Guenée) (Insecta: Lepidoptera: Pyralidae). Ecotoxicol. Environ. Saf. 2006, 65, 102–107. [Google Scholar] [CrossRef] [PubMed]
  43. Hancock, P.A. Combining fungal biopesticides and insecticide-treated bednets to enhance malaria control. PLoS Comput. Biol. 2009, 5, e1000525. [Google Scholar] [CrossRef] [PubMed]
  44. Köhl, J.; Kolnaar, R.; Ravensberg, W.J. Mode of action of microbial biological control agents against plant diseases: Relevance beyond efficacy. Front. Plant Sci. 2019, 10, 1–19. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  45. Ikbal, C.; Pavela, R. Essential oils as active ingredients of botanical insecticides against aphids. J. Pest Sci. 2019, 92, 971–986. [Google Scholar] [CrossRef]
  46. Lacey, L.A.; Grzywacz, D.; Shapiro-Ilan, D.I.; Frutos, R.; Brownbridge, M.; Goettel, M.S. Insect pathogens as biological control agents: Back to the future. J. Invertebr. Pathol. 2015, 132, 1–41. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  47. Rahim, M. Biological activity of azadirachtin-enriched neem kernel extracts against Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) in stored wheat. J. Stored Prod. Res. 1998, 34, 123–128. [Google Scholar] [CrossRef]
  48. Tofel, H.K.; Nukenine, E.N.; Stahler, M.; Adler, C. Degradation of azadirachtin A on treated maize and cowpea and the persistence of Azadirachta indica seed oil on Callosobruchus maculatus and Sitophilus zeamais. J. Stored Prod. Res. 2016, 69, 207–212. [Google Scholar] [CrossRef]
  49. Kavallieratos, N.G.; Athanassiou, C.G.; Saitanis, C.J.; Kontodimas, D.C.; Roussos, A.N.; Tsoutsa, M.S.; Anastassopoulou, U. Effect of two azadirachtin formulations against adults of Sitophilus oryzae and tribolium confusum on different grain commodities. J. Food Prot. 2007, 70, 1627–1632. [Google Scholar] [CrossRef]
  50. Robertson, J.L.; Preisler, H.K. Pesticide Bioassays with Arthropods; CRC: Boca Raton, FL, USA, 1992. [Google Scholar]
  51. Xie, Y.S.; Fields, P.G.; Isman, M.B. Repellency and toxicity of azadirachtin and neem concentrates to three stored-product beetles. J. Econ. Entomol. 1995, 88, 1024–1031. [Google Scholar] [CrossRef]
  52. Liu, X.; Zhang, Q.; Xu, B.; Li, J. Effects of Cry1Ac toxin of Bacillus thuringiensis and nuclear polyhedrosis virus of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) on larval mortality and pupation. Pest Manag. Sci. 2006, 62, 729–737. [Google Scholar] [CrossRef]
  53. Moscardi, F. Assessment if the application of baculoviruses for the control of Lepidoptera. Annu. Rev. Entomol. 1999, 44, 257–289. [Google Scholar] [CrossRef] [PubMed]
  54. Hernández, A.F.; Gil, F.; Lacasaña, M. Toxicological interactions of pesticide mixtures: An update. Arch. Toxicol. 2017, 91, 3211–3223. [Google Scholar] [CrossRef] [PubMed]
  55. Espinel-Correal, C.; López-Ferber, M.; Zeddam, J.-L.; Villamizar, L.; Gómez, J.; Cotes, A.M.; Léry, X. Experimental mixtures of Phthorimaea operculella granulovirus isolates provide high biological efficacy on both Phthorimaea operculella and Tecia solanivora (Lepidoptera: Gelechiidae). J. Invertebr. Pathol. 2012, 110, 375–381. [Google Scholar] [CrossRef] [PubMed]
  56. Bhuiyan, K.R.; Hassan, E.; Isman, M.B. Growth inhibitory and lethal effects of some botanical insecticides and potential synergy by dillapiole in Spodoptera litura (Fab.) (Lepidoptera: Noctuidae). J. Plant Dis. Prot. 2000, 108, 82–88. [Google Scholar]
  57. Khorrami, F.; Valizadegan, O.; Forouzan, M.; Soleymanzade, A. The antagonistic/synergistic effects of some medicinal plant essential oils, extracts and powders combined with Diatomaceous earth on the flour beetle, Tribolium castaneum Herbst (Coleoptera: Tnenebrionidae). Arch. Phytopathol. Plant Prot. 2018, 51, 13–14. [Google Scholar] [CrossRef]
Table
Table 1. Mean (%) mortality and median survival time (days) of adults of S. zeamais, R. dominica, P. truncatus and T. granarium treated separately with cannabidiol (CBD) oil, Azatin, Helicovex and Madex after 28 days. Mean% mortality for different concentrations or biopesticide, within the same insect and pathogen, followed by the same small letter are not significantly different. Mean% mortality for different insect, within the same concentrations or biopesticide, followed by the same capital letter are not significantly different (Bonferroni test, a = 0.05). Estimate Median survival time (days) of the same insect followed by the same small letter are not significantly different (Kaplan–Meier, a = 0.05). * Median Survival Time (S. zeamais: F: 11.000; df: 6; p = 0.225, R dominica: F: 1.565; df:6; p = 0.975, P. truncatus: F: 1.259; df: 6; p = 0.877, T. granarium: F: 1.240; df: 6; p = 0.893) (n = 200).
Table 1. Mean (%) mortality and median survival time (days) of adults of S. zeamais, R. dominica, P. truncatus and T. granarium treated separately with cannabidiol (CBD) oil, Azatin, Helicovex and Madex after 28 days. Mean% mortality for different concentrations or biopesticide, within the same insect and pathogen, followed by the same small letter are not significantly different. Mean% mortality for different insect, within the same concentrations or biopesticide, followed by the same capital letter are not significantly different (Bonferroni test, a = 0.05). Estimate Median survival time (days) of the same insect followed by the same small letter are not significantly different (Kaplan–Meier, a = 0.05). * Median Survival Time (S. zeamais: F: 11.000; df: 6; p = 0.225, R dominica: F: 1.565; df:6; p = 0.975, P. truncatus: F: 1.259; df: 6; p = 0.877, T. granarium: F: 1.240; df: 6; p = 0.893) (n = 200).
InsectConcentration (ppm)MortalityMedian Survival Time (Days) *
CBD
Oil		AzatinHelicovexMadex(%)SdEstimateSd95% Confidence Interval
Lower BoundUpper Bound
S. zeamais000062.0027.160a0.51026.16028.160
50000038bA3.9022.260b1.25119.80924.711
150000054dA1.4021.140b1.18418.81923.461
300000070eA10.017.920c1.27415.42420.416
015000046cA1.4023.800b0.95021.93925.661
001500016aA3.9026.180a0.78724.63827.722
000150018aA3.4026.180a0.69024.82727.533
R. dominica000062.0027.300a0.426.50028.100
50000044bA5.2021.280b1.26618.79823.762
150000060cA2.2020.720b1.15518.45522.985
300000084dA5.5015.380c1.22813.27218.088
015000044bA1.4023.240b1.06221.15925.321
001500020aA5.1025.480b0.90423.70827.252
000150022aA4.5025.620b0.79424.06427.176
P. truncatus000063.0027.020a0.56025.92228.118
50000048bA3.5021.140b1.18318.82123.459
150000058bA4.8020.720b1.26218.24623.194
300000080cA10.015.920c1.22913.87118.689
015000050bA4.2022.960b1.09320.81725.103
001500020aA7.1025.200a0.97923.28127.119
000150020aA7.1026.180a0.72224.76627.594
T. granarium000082.0027.020a0.62625.79228.248
50000044aA5.2021.700b1.25319.24424.156
150000054bA2.2020.700b1.16318.42022.980
300000062cA2.3019.600c1.22417.20121.999
015000038aA4.5023.800b0.95321.93325.667
001500020aA7.1025.620a0.87623.90327.337
000150024aA5.5026.740a0.53725.68727.793
Table
Table 2. Mean% mortality and median survival time (days) adults of S. zeamais, R. dominica, P. truncatus and T. granarium treated with CBD oil in combination with Azatin, Helicovex and Madex. Mean% mortality for different concentrations or biopesticide, within the same insect and pathogen, followed by the same small letter are not significantly different; mean% mortality for different insect, within the same concentrations or biopesticide, followed by the same capital letter are not significantly different (Bonferroni test, a = 0.05). Estimate median survival time (days) of the same insect followed by the same small letter are not significantly different (Kaplan–Meier, a = 0.05). * Median survival time (S. zeamais: F: 0.207; df: 8; p = 0.936, R dominica: F: 0.565; df: 8; p = 0.975, P. truncatus: F: 3.667; df: 8; p = 0.230, T. granarium: F: 0.125; df: 8; p = 0.975).
Table 2. Mean% mortality and median survival time (days) adults of S. zeamais, R. dominica, P. truncatus and T. granarium treated with CBD oil in combination with Azatin, Helicovex and Madex. Mean% mortality for different concentrations or biopesticide, within the same insect and pathogen, followed by the same small letter are not significantly different; mean% mortality for different insect, within the same concentrations or biopesticide, followed by the same capital letter are not significantly different (Bonferroni test, a = 0.05). Estimate median survival time (days) of the same insect followed by the same small letter are not significantly different (Kaplan–Meier, a = 0.05). * Median survival time (S. zeamais: F: 0.207; df: 8; p = 0.936, R dominica: F: 0.565; df: 8; p = 0.975, P. truncatus: F: 3.667; df: 8; p = 0.230, T. granarium: F: 0.125; df: 8; p = 0.975).
InsectCombined Concentration (ppm)MortalityMedian Survival Time (Days) *
CBD
Oil		AzatinHelicovexMadex(%)SdEstimateSd95% Confidence Interval
Lower BoundUpper Bound
S. zeamais50015000036aA4.9025.060a0.79323.50626.614
150015000068cA1.9820.440b1.04118.39922.481
300015000084dA3.4815.400c1.23512.97917.821
50001500030aA5.0024.360a1.00922.38226.338
150001500046bA5.4823.080a0.95321.21224.948
300001500062cA1.3721.000b1.15618.73423.266
50000150018aA4.3725.900a0.72724.47527.325
150000150022aA3.0425.060a0.95423.19126.929
300000150040aA1.0722.960b1.09520.81425.106
R dominica50015000050bA10.022.680a1.02020.68124.679
150015000080dA5.8018.060a1.08115.94120.179
300015000090eB1.0714.140b1.17611.83516.445
50001500040bA5.8023.380a1.08721.25025.510
150001500060cA2.2522.260a1.07920.14524.375
300001500070cA1.0719.880a1.19517.53922.221
50000150032aB4.4023.520a1.07221.41925.621
150000150042bB2.3022.820a1.08920.68624.954
300000150060cB4.1421.000a1.17418.69923.301
P. truncatus50015000044dA2.3723.520a1.00821.54425.496
150015000074fA5.1719.320a1.07217.21821.422
300015000094gB5.4013.300b1.11911.10715.493
50001500038cA2.3723.520a1.07221.41925.621
150001500054eB1.4022.960a1.04920.90425.016
300001500070fA3.0726.765a1.19824.41629.114
50000150026aB1.4024.220a1.05522.15226.288
150000150030bC2.2524.220a1.02922.20326.237
300000150052eC3.0421.000a1.17718.69223.308
T. granarium50015000050bA1.0722.680a1.06120.60124.759
150015000056bB2.9421.420a1.18319.10223.738
300015000062cC2.3720.580a1.21318.20322.957
50001500046aA3.4822.820a1.10520.65424.986
150001500054bA3.4022.260a1.13620.03424.486
300001500068cA2.3720.440a1.22018.04922.831
50000150038aB5.9523.660a1.07421.55425.766
150000150048aD3.3723.52a01.00621.54825.492
300000150054bC3.4822.680a1.05920.60424.756
Table
Table 3. Observed and expected mortality of S. zeamais, R. dominica, P. truncatus and T. granarium adults at the end of the experiment (28 days) treated with CBD oil in combinations with Azatin, Helicovex and Madex, plus their interaction (A = Additive. C = Competitive. S = Synergistic) (n = 200). * Expected mortality is calculated according to Robertson and Preisler [51].
Table 3. Observed and expected mortality of S. zeamais, R. dominica, P. truncatus and T. granarium adults at the end of the experiment (28 days) treated with CBD oil in combinations with Azatin, Helicovex and Madex, plus their interaction (A = Additive. C = Competitive. S = Synergistic) (n = 200). * Expected mortality is calculated according to Robertson and Preisler [51].
Combined Concentration (ppm)Mortality (%)χ2
(1 df; p = 0.05)		Interaction
CBD
Oil		AzatinHelicovexMadexObservedExpected *
S. zeamais
500150000366824.53C
1500150000687614.33C
300015000084840.023A
50001500030518.864C
150001500046647.512C
300001500062766.224C
500001500185223.452C
1500001500226439.543C
3000001500407638.247C
R dominica
500150000507010.129C
150015000080780.033A
300015000090910.161A
50001500040576.562C
150001500060692.339A
3000015000708715.251C
500001500325814.995C
1500001500427019.831C
3000001500608838.586C
P. truncatus
500150000447526.968C
150015000074801.236A
300015000094900.678A
500015000386011.007C
150001500054684.808C
300001500070848.757C
500001500266025.568C
1500001500306834.148C
3000001500528542.509C
T. granarium
50015000050687.499C
150015000056738.150C
300015000062783.139A
50001500046583.372A
150001500054663.292A
300001500068720.403A
500001500386010.952C
150000150048679.017C
300000150054739.675C
Table
Table 4. Toxicity variables in the equation from Cox regression for the treatments against S. zeamais, R. dominica, P. truncatus and T. granarium adults at the end of Table. 28 days. † B: B values are associated with increased hazard and decreased survival time; as the predictor increases, the hazard of the event increases and the predicted survival duration decreases. Negative coefficients indicate decreased hazard and increased survival times. †† Exp (B): the ratio of hazard rates.
Table 4. Toxicity variables in the equation from Cox regression for the treatments against S. zeamais, R. dominica, P. truncatus and T. granarium adults at the end of Table. 28 days. † B: B values are associated with increased hazard and decreased survival time; as the predictor increases, the hazard of the event increases and the predicted survival duration decreases. Negative coefficients indicate decreased hazard and increased survival times. †† Exp (B): the ratio of hazard rates.
Variables in the Equation
Combined Concentration
(ppm)		B †SdSig.Exp (B) ††95.0% CI for Exp (B)
LowerUpper
CBD 500–Madex 1500−0.3540.1670.0340.7020.5060.973
CBD 1500–Madex 1500−0.2170.1600.1760.8050.5881.102
CBD 3000–Madex 15000.2540.1460.0821.2890.9681.716
CBD 500–Helicovex 1500−0.1130.1570.4710.8930.6571.215
CBD 1500–Helicovex 15000.2350.1450.1061.2650.9511.681
CBD 3000–Helicovex 15000.5930.1380.0001.8101.3812.373
CBD 500–Azatin 15000.0550.1500.7131.0570.7871.419
CBD 1500–Azatin 15000.6700.1370.0001.9551.4952.556
CBD 3000–Azatin 15001.0880.1330.0002.9692.2883.853
Separately Concentration
(ppm)
CBD 5000.0820.1530.0071.0850.8041.465
CBD 15000.3960.1430.0001.4851.1231.964
CBD 30000.8580.1360.0002.3591.8073.080
Control−1.9640.2880.8300.1400.0800.247
Helicovex 1500−0.9060.1950.4100.4040.2760.592
Madex 1500−0.9280.2150.5920.3960.2590.603
Azatin 1500−0.8790.1910.3150.4150.2850.604

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Mantzoukas, S.; Kalyvas, N.; Ntoukas, A.; Lagogiannis, I.; Farsalinos, K.; Eliopoulos, P.A.; Poulas, K. Combined Toxicity of Cannabidiol Oil with Three Bio-Pesticides against Adults of Sitophilus Zeamais, Rhyzopertha Dominica, Prostephanus Truncatus and Trogoderma Granarium. Int. J. Environ. Res. Public Health 2020, 17, 6664. https://doi.org/10.3390/ijerph17186664

AMA Style

Mantzoukas S, Kalyvas N, Ntoukas A, Lagogiannis I, Farsalinos K, Eliopoulos PA, Poulas K. Combined Toxicity of Cannabidiol Oil with Three Bio-Pesticides against Adults of Sitophilus Zeamais, Rhyzopertha Dominica, Prostephanus Truncatus and Trogoderma Granarium. International Journal of Environmental Research and Public Health. 2020; 17(18):6664. https://doi.org/10.3390/ijerph17186664

Chicago/Turabian Style

Mantzoukas, Spiridon, Nikolaos Kalyvas, Aristeidis Ntoukas, Ioannis Lagogiannis, Konstantinos Farsalinos, Panagiotis A. Eliopoulos, and Konstantinos Poulas. 2020. "Combined Toxicity of Cannabidiol Oil with Three Bio-Pesticides against Adults of Sitophilus Zeamais, Rhyzopertha Dominica, Prostephanus Truncatus and Trogoderma Granarium" International Journal of Environmental Research and Public Health 17, no. 18: 6664. https://doi.org/10.3390/ijerph17186664

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