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Article

Assessing the Impact of Variety, Irrigation, and Plant Distance on Predatory and Phytophagous Insects in Chili

by
András Lajos Juhász
1,
Márk Szalai
2 and
Ágnes Szénási
1,*
1
Department of Integrated Plant Protection, Plant Protection Institute, Hungarian University of Agriculture and Life Sciences, 2100 Gödöllő, Hungary
2
Vak Bottyán str. 20, 2100 Gödöllő, Hungary
*
Author to whom correspondence should be addressed.
Horticulturae 2022, 8(8), 741; https://doi.org/10.3390/horticulturae8080741
Submission received: 26 July 2022 / Revised: 13 August 2022 / Accepted: 16 August 2022 / Published: 17 August 2022
(This article belongs to the Special Issue Integrated Pest Management in Horticulture)
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Abstract

:
Chilies are plants that are becoming increasingly popular all over the world, including in Hungary. Since little is known about the abundance and seasonal dynamic of insect pests and their natural enemies associated with chilies under Hungarian climatic conditions, the aim of the study was to monitor these organisms on different varieties under different growing conditions to provide data for improving IPM for chilies. Chili varieties “Yellow Scotch Bonnet” (YSB) and “Trinidad Scorpion Butch T” (TSBT) were planted with three replicates. Two different plant-to-plant distances (30 vs. 40 and 40 vs. 60 cm in YSB, TSBT, respectively) and two different irrigation frequencies (daily, 40 min; every second day, 20 min) were used. Fifty flowers/plot/date were collected. In 2019, Orius (Hemiptera: Anthocoridae) larvae, and in 2021, phytophagous thrips larvae were dominant in all the treatments. Significantly more Orius adults and larvae were found in the YSB than in the TSBT variety and the number of Aeolothrips and phytophagous thrips (Thysanoptera: Thripidae) adults was significantly higher under less irrigation in 2019. The plant spacing did not affect the abundance of predators or herbivores. Upon comparing the two years, no effect of the treatments on the studied insect taxa was observed.

1. Introduction

Capsicum species belonging to the Solanaceae family are among the most popular and widely consumed spice plants [1] and they have been cultivated for about 6000 years [2]. The worldwide production and harvested area of green peppers and chilies have increased in the last decade [3]. Possibly due to the capsaicinoid produced only by Capsicum species, peppers were used as a medicinal plant in ancient times [4]. Capsaicinoid extracts have medicinal properties, which can help to stop the pain of arthritis (rheumatoid arthritis and osteoarthritis) and arterial diseases [5]. Due to their pungency deriving from their capsaicinoid contents, chilies are very popular in the cuisines of America, Asia, Africa and Europe [6]. In addition, the green fruits of different pepper genotypes are rich sources of vitamins A, C and E [7]. Moreover, the first extraction of vitamin C was first successfully conducted in 1928 by Hungarian biochemist Albert Szent-Györgyi from sweet peppers, and this achievement led to him being awarded the Nobel Prize in physiology and medicine in 1937 [7].
Agrotechnological factors such as balanced irrigation and proper plant spacing help in the prevention of exposure to harmful organisms, an element of the first principle of integrated pest management (Directive 2009/128/EC) [8]. Due to their sensitivity to water stress [9], for optimal yield and quality, Capsicum species need an adequate water supply [10]. Drip irrigation systems are able to save water [11,12] and optimize the water supply, improving yield and delivering water directly to the roots [13]. Among agrotechnical methods, the manipulation of plant spacing is one of the most favored and promising ways of reducing pests [14]. Plant spacing and row spacing have important impacts on the plant growth, width and yield of chili pepper [15]. Above a certain plant density, nutrients, sunlight and water become less available because of the competition between plants [16]. Closer plant spacing generates higher relative humidity, which creates advantageous conditions for pathogens [16]. In the lower parts of plants, light leakage and aeration are heavily reduced by higher plant spacing and this also obstructs pollination [16] On the other hand, significantly more flowers and fruits were observed with an increase in plant density [15]. Therefore, a good compromise is necessary to determine the right plant spacing.
Although the rate of pestivorous species is only around 1% of the 6377 described known species in the order Thysanoptera [17,18], thrips are important insect pests in pepper, damaging different plant parts such as the leaves, flowers and fruits [19], as well as transmitting plant viruses such as Groundnut ringspot virus (GRSV), Tomato chlorotic spot virus (TCSV), Tomato spotted wilt virus (TSWV) and Watermelon silver mottle virus (WSMV) [20,21]. The following Thysanoptera species are reported as pests of Capsicum spp.: in Europe, Franklinella occidentalis (Pergande) and Thrips tabaci Lindeman; in North America, Frankliniella bispinosa (Morgan), Frankliniella fusca (Hinds), F. occidentalis, Frankliniella tritici (Fitch), and T. tabaci; in South Africa and South Asia, Frankliniella schultzei (Trybom); in Japan, Brazil and the Caribbean region, Thrips palmi Karny; in Java, Indonesia, Thrips parvispinus (Karny); and, furthermore, in India, Scirtothrips dorsalis Hood [19,22,23,24,25]. The identified thrips vectors of the abovementioned tospoviruses infecting Capsicum species are F. bispinosa (TSWV), F. fusca (TSWV), Frankliniella intonsa (Trybom) (TCSV and TSWV), F. occidentalis (GRSV, TCSV, and TSWV), F. schultzei (GRSV, TCSV, and TSWV), T. palmi (WSMV), Thrips setosus (Moulton) (TSWV) and T. tabaci (TSWV) [21]. Among Thysanoptera, beneficial species can also be found. Species belonging to the Aeolothrips genus are mainly flower-dwelling and predators [18]. The Hungarian Thysanoptera checklist consists of eight Aeolothrips species [26] and among them, Aeolothrips intermedius Bagnall is widespread in Europe [27] and frequent in Hungary as well [28], occurring in different biotopes, mainly on dicotyledonous herbaceous plants [29]. Pollen can serve as an important alternative food for A. intermedius [30,31].
Orius species (Heteroptera: Anthocoridae) are generalist predators, but they prefer Thysanoptera from the family Thripidae [32]. They are abundant all over the world, are able to invade field crops rapidly, and, furthermore, can effectively control the population of thrips species under field conditions [33,34,35,36] since they can prey on up to 10 thrips individuals/day [37]. Orius niger W. and Orius minutus L. are the most frequent species from this genus in Hungary) [38].
Boateng et al. (2017) [16] observed the hot pepper plant morphology and yield with various plant spacing (70 × 30, 70 × 40, and 70 × 50 cm) in Ghana. Setiawati et al. (2022) [15] studied the effects of different plant densities (20,000, 30,000 or 40,000 plants ha−1) on disease and pest susceptibility in chilies in Indonesia. Among the arthropod pests, only thrips damage was reported, which was reduced with a decrease in plant density. Das et al. (2021) [14] observed an effect of plant spacing (50 × 60, 50 × 50, 50 × 40, and 50 × 30 cm) on the incidence of chili leaf curl virus in hot peppers in Bangladesh, but not on arthropod pests. O’Keefe and Palada (2002) [39] studied only the row spacing (41, 46 and 61 cm) in U.S. Virgin Islands, but no effect of the plant-to-plant distance on the yield and growth of chilies was observed, and they performed no arthropod observations. Karungi et al. (2013) [40] assessed the effect of plant (80 × 80 vs. 60 × 50 cm) density on aphids, thrips, whiteflies and viruses in the Scotch Bonnet hot chili variety in Uganda. Closer plant spacing decreased the aphid and whitefly abundances but not the abundance of thrips. There are no data available on the effects of irrigation on the insect density and population growth in chilies. Since little is known about the abundance and seasonal dynamics of insect pests and their natural enemies associated with chilies under European conditions, the aim of this study was to monitor these organisms on different varieties under different growing conditions to provide data for improving the IPM of chilies in Europe.

2. Materials and Methods

2.1. Experimental Design

Study was carried out at the experimental farm of the Institute of Horticultural Science, Hungarian University of Agriculture and Life Sciences, Gödöllő, Hungary (47.58 N, 19.37 E). In total, twenty-four plots were established on sandy clay loam soil. The plot size was determined according to the number of available seedlings. The same adjustments were carried out for both years. However, in 2021, due to the low plant germination rate and the weather circumstances in May (continuous cloudy weather and rainfall), the sizes of the plots and of the experimental area were smaller than those in 2019.
Two chili (Capsicum chinense Jacq.) varieties (Trinidad Scorpion Butch T, Yellow Scotch Bonnet) were planted in plots of 12.96 m2 (3.6 × 3.6 m) in the year 2019 and 2.16 m2 (1.8 m × 1.2 m) in the year 2021. Eight different combinations of settings were used. Each variety was planted in two different plant spacings according to their usual plant height values, and two different irrigation frequencies/variety by drip irrigation was used. The number of replicates was three. Since 61 cm was found to be the optimal row spacing in the study of O’Keefe and Palada (2002) [39], we decided to use 60 cm row spacing for both varieties in our experiment.
The coding of the treatments was as follows:
V1: 
TSBT
V2: 
YSB
V1PS1: 
Plant spacing of 60 cm
V1PS2: 
Plant spacing of 40 cm
V2PS1: 
Plant spacing of 40 cm
V2PS2: 
Plant spacing of 30 cm
I1: 
Irrigation daily, 40 min (7.33 L/m/day)
I2: 
Irrigation every second day, 20 min (3.66 L/m/two days)
Seeds of the YSB variety were obtained from Caribbean Garden Seed, USA, and those of the TSBT variety, from Samenchilishop, Germany. Seeds were sowed in seedling trays on 12 March in 2019 and 7 April in 2021 and were placed, first, in a germination chamber and, later, in a nursery. Seed dressing using spores of the Pythium oligandrum mycoparasite fungus was performed each year.
Seedlings were planted on 24 May 2019 and 25 June 2021. Plants were harvested on 11–12 September in 2019 and 11 October in 2021. After planting, no pesticide applications were used during the growing seasons.

2.2. Characteristics of the Studied Varieties

TSBT is one of the six hottest chilies of the world [4], its pungency is between 800,000 and 1,460,000 on the Scoville-scale [41]. The landrace Trinidad Scorpion originates from Trinidad and Tobago. ‘Butch T’ means that it is grown by Butch Taylor in Australia [42]. The plant height ranges between 100 and 200 cm. It is a fast-maturing variety since only 90 to 120 days are needed for its ripening [43], depending on environmental conditions. YSB is one of the most widespread chili varieties in the Caribbean region and is grown extensively in Jamaica. Its SHU (Scoville Heat Unit) value ranges from 200,000 to 350,000; a slow-growing, bushy variety, with a maximum height of 50 cm. For its ripening, 160 days are needed [44].

2.3. Meteorological Data

Weather data (daily minimum, maximum and average temperature and precipitation) were obtained from Meteoblue AG (Basel, Switzerland) for both vegetation periods (Figure 1).

2.4. Flower Sample Collection

Observation begun two weeks later than start of flowering. In both years, ten plants per plot were randomly selected and five flowers per plant were collected and stored in a plastic tube containing 60% propanol. Thysanoptera (phytophagous and predatory species) and Orius adults and larvae were counted using a stereomicroscope.

2.5. Statistical Analysis

Data were aggregated and analyzed using R [45] with Rcmdr package [46]. Generalized linear models were used to investigate individually the effect of variety/irrigation frequency/plant spacing as single explanatory variables on the abundance of predatory bugs (Orius spp.) and phytophagous and predatory Thysanoptera individuals. For all the hypothesis tests, a threshold of alpha = 5% was used to control type I error. However, there was no specific control factor for beta / type II error. However, we used the tests with the highest power possible (considering the assumptions), and this way we could minimize type II error. Moreover, we fitted models individually for variety/irrigation frequency/plant spacing as single explanatory variables on abundances, and these variables had two levels. Therefore, no p-value adjustment was performed for multiple comparisons. In the case of a low number of individuals, Poisson models were fitted; otherwise, Gaussian models. Assumptions of residual normality and homoscedasticity as well as potential influential data points were checked with basic model diagnostic plots [47].

3. Results

3.1. Abundance of Predatory and Phytophagous Insects by Treatments

Altogether, 117 Aeolothrips adults, 160 Aelothrips larvae, 316 Orius adults, 1451 Orius larvae, 805 phytophagous thrips adults and 1287 phytophagous thrips larvae were collected in chili flowers during the two years. In 2019, Orius larvae and phytophagous thrips adults were the most numerous taxa, while in 2021, phytophagous thrips larvae and Orius larvae were the most abundant taxa (Table 1 and Table S1). The individual numbers of each taxon were similar for the different treatments. In the first year, the most specimens were found in the plots with less irrigation, in the second vegetation period, in the plots with increased plant spacing (Table S1).
In the year 2019, significantly more Orius adults (p < 0.001) and larvae (p = 0.0135) were found in the flowers of the YSB variety, but the numbers of these insects were similar under the different irrigation treatments and plant spacing (Figure 2A). The abundances of phytophagous thrips larvae did not differ between the treatments (Figure 2B). As for the number of all the Orius individuals (larvae and adults together), a significant difference between the two varieties was detected (p = 0.00119, Figure 2C). The numbers of all phytophagous thrips (larvae and adults together), phytophagous thrips and Aeolothrips adults were significantly higher under less irrigation (p = 0.00916, p = 0.0098, p < 0.001, respectively), while the abundances of Aeolothrips larvae did not differ between the treatments (Figure 2B–D, also see Table 2).
In the year 2021, the numbers of phytophagous thrips larvae were significantly higher (p = 0.0266) under more irrigation, while the abundances of all the other taxa did not differ between the treatments (Figure 3A–D; also, see Table 3). Upon pooling the two years’ data, no effects of the treatments on insect taxa were observed.

3.2. Seasonal Dynamics

The average numbers of individuals for all the taxa except for Orius larvae; for some of the dates, Aeolothrips larvae decreased to August; and the insect abundance was always below 10 specimens in all the treatments. For almost all the dates and treatments, more phytophagous thrips adults were found in the flowers than larvae (Figure 4). The seasonal dynamics of certain insect taxa were similar in the flowers of both varieties (Figure 4A,B); however, on almost all the dates, more thrips adults were collected in the less-irrigated plots than under increased irrigation (Figure 4C,D). Except for on a single date, the number of phytophagous thrips larvae and Orius larvae was always slightly higher under decreased plant spacing than under a higher plant density (Figure 4E,F).
Phytophagous thrips larvae were dominant, except on 13 September, and Aeolothrips adults were the less-numerous insects in the vegetation period in all the treatments. Besides phytophagous thrips larvae, only Orius larvae could reach five individuals on some dates, and the number of other taxa was always below this value. On all the dates, more Orius larvae were present in the flowers than adults (Figure 5). The seasonal dynamics of certain insect groups were similar in the flowers of both varieties (Figure 5A,B). On almost all the dates, more Orius adults and larvae but fewer phytophagous thrips were found under less irrigation than in the more frequently irrigated plots (Figure 5C,D). Except for on two dates, the larval number of phytophagous thrips and Orius spp. was always slightly higher under decreased plant spacing than under an increased plant density (Figure 5E,F).

4. Discussion

This is the first time the insect communities of chili flowers in the European region have been studied. The literature data on the arthropods found in chili flowers are relatively scarce; moreover, simultaneous data collection for different irrigation frequencies and plant spacing is also limited.
Temperature and rainfall are the most important weather factors affecting thrips populations under field conditions. Warm, sunny and dry weather in the summer are favorable for the survival and population growth of most thrips species in temperate zones [48]. Probably due to this circumstance, the number of Thysanoptera adults and all phytophagous thrips was significantly higher under decreased irrigation than under increased irrigation, but only in the first year. Furthermore, the largest abundance of these taxa was detected in the less-irrigated plots. On the contrary, the phytophagous thrips abundance was similar at higher and lower irrigation levels in 2021. No effect of the irrigation frequency on Orius spp was observed.
Effects of the studied varieties were detected only on predatory bugs. The abundance of Orius spp. (larvae, adults and together) was significantly higher, whereas the thrips abundance (regardless of the species or developmental stages) was significantly lower on the YSB variety in 2019. The number of Orius and Thysanoptera individuals on the same variety was similar in the second study year.
No effect of the varieties on phytophagous thrips was found, since the adult and larval numbers of these insects on the two varieties were similar in 2019 and in 2021. On the other hand, different thrips resistance levels have been detected in different Capsicum species (C. annuum, C. chinense, C. baccatum and C. frutescens) and varieties [19,49,50]. Moreover, there are also chili pepper varieties that are resistant to other animal pests such as the oriental fruit fly (Bactrocera dorsalis) [51,52] and the southern root-knot nematode (Meloidogyne incognita) [53].
Two different plant densities (60 × 50 and 80 × 80 cm) were performed with a 4 × 8 m plot size for the Scotch Bonnet (Capsicum chinense) variety, and the plant spacing had no significant effect, but the vegetation period and sampling date had a significant effect on phytophagous thrips abundance [40]. Setiawati et al. (2022) [15] found that plant density could effectively influence chili pepper quality and thrips damage. Three different plant densities (20,000, 30,000 and 40,000 plants ha−1) with 13 × 14 m plot size were used. Less thrips damage was detected under the lowest plant density, followed by densities of 30,000 and 40,000 plants ha−1. On the contrary, our results indicated that the insect abundances were similar under different plant spacing both years.
The flower, as a habitat, may ensure protection from rainfall, unfavorable temperatures, solar radiation and (due to the higher relative humidity) desiccation for the thrips species [54]. However, the number of suitable flowers within an area might influence thrips population density, and among others, due to this circumstance, Thysanoptera species have great mobility within and between habitats [48]. In our studies, beside phytophagous thrips individuals, Orius and Aeolothrips species were found in chili flowers, which are among the primary predators of Thysanoptera [48]. Similarly, in field melons primarily infested with thrips, the main predators in the flowers were Orius spp. (67.4%) and Aeolothrips spp. (32.6%) [55].
Similarly to the results of Sabelis and Van Rijn (1997), Funderburk et al. (2000) and Ramachandran et al. (2001) [33,34,35], we also found that Orius predatory bugs were abundant and could effectively control the individual number of Thysanoptera species under field conditions in the first year. It was observed that predators were responding to the number of Thrips tabaci individuals in onions [56], and, in parallel to this, our experience was that the Orius larval number was increased in the vegetation period of the year 2019, whereas the phytophagous thrips abundance was decreased. However, an opposite trend was detected in 2021, and the Orius population was not be able to follow the prey abundance. On the other hand, this type of response of Aeolothrips species could not be observed, probably because of their low abundance. The number of this predatory organism declined progressively in 2019, and few adults were found in the next season. Although Orius species prefer Thysanoptera from the Thripidae family [32], Orius albidipennis was able to prey on Aeolothrips fasciatus from the Aeolothripidae family and reduce its number in the field [57]. Furthermore, intraguild predation was discovered between Orius niger and Aeolothrips intermedius [58]. Therefore, Orius species may also regulate predatory thrips populations in chili flowers. However, in our observations, Aeolothrips individuals were much less abundant than Orius specimens, especially in the second year.
Since plant genetic diversity is an important element of integrated plant protection for chilies [59], the investigation of more Capsicum species and varieties in future research will be worthwhile.

5. Conclusions

Based on our trials with chili cultivation practices, we conclude that a higher drip irrigation frequency and water amount negatively impacted the number of adults of phytophagous and predatory Thysanoptera in the first year of the study. These results might be considered in chili cultivation, depending on the environmental conditions, e.g., the season and soil type with special regard to the climate. The chili varieties in our study resulted in an impact on the density of the predatory Orius species but not that of other insects species; however, further tests on other varieties should also be assessed. We found that the plant spacing of the chilies did not affect the abundance of predators or herbivores. According to our observations, Orius predatory bugs are key species in chili cultivation; therefore, the protection of these predators as non-target organisms in the IPM of chilies is an important aspect to be considered. Our results provide important support for the development of IPM for chilies.

Supplementary Materials

The following supporting information can be downloaded at: www.mdpi.com/article/10.3390/horticulturae8080741/s1, Table S1: Total individual numbers of insects in chili flowers under treatments.

Author Contributions

Conceptualization, Á.S. and A.L.J.; methodology, Á.S. and A.L.J.; investigation, A.L.J.; data curation, M.S. and A.L.J.; writing—original draft preparation, Á.S., M.S. and A.L.J.; writing—review and editing, Á.S., M.S. and A.L.J.; visualization, A.L.J., M.S. and Á.S.; supervision, Á.S. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data are available on request due to institutional restrictions and privacy.

Acknowledgments

The authors would like to thank everyone who contributed to this article and the field and laboratory work.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Garcés-Claver, A.; Arnedo-Andrés, M.S.; Abadía, J.; Gil-Ortega, R.; Álvarez-Fernandez, A. Determination of capsaicin and dihydrocapsaicin in Capsicum fruits by liquid chromatography–electrospray/time-of-flight mass spectrometry. J. Agric. Food Chem. 2006, 54, 9303–9311. [Google Scholar] [CrossRef]
  2. Perry, L.; Dickau, R.; Zarrillo, S.; Holst, I.; Pearsall, D.M.; Piperno, D.R.; Berman, M.J.; Cooke, R.G.; Rademaker, K.; Ranere, A.J.; et al. Starch fossils and the domestication and dispersal of chili peppers (Capsicum spp. L.) in the Americas. Science 2007, 315, 986–988. [Google Scholar] [CrossRef]
  3. FAOSTAT. 2022. Available online: https://www.fao.org/faostat/en/#data/QCL/visualize (accessed on 1 July 2022).
  4. Omolo, M.A.; Wong, Z.Z.; Mergen, A.K.; Hastings, J.C.; Le, N.C.; Reiland, H.A.; Case, K.A.; Baumler, D.J. Antimicrobial properties of chili peppers. J. Infect. Dis. Ther. 2014, 2, 145. [Google Scholar] [CrossRef]
  5. Cordell, G.A.; Araujo, O.E. Capsaicin: Identification, nomenclature, and pharmacotherapy. Ann. Pharmacother. 1993, 27, 330–336. [Google Scholar] [CrossRef] [PubMed]
  6. Guzmán, I.; Bosland, P.W. Sensory properties of chile pepper heat—And its importance to food quality and cultural preference. Appetite 2017, 117, 186–190. [Google Scholar] [CrossRef] [PubMed]
  7. Kumar, S.; Kumar, R.; Singh, J. Cayenne/American Pepper. In Handbook of Herbs and Spices, 1st ed.; Peter, K.V., Ed.; Woodhead Publishing: Cambridge, UK, 2006; Volume 3, pp. 299–312. [Google Scholar]
  8. Barzman, M.; Bàrberi, P.; Birch, A.N.; Boonekamp, P.; Dachbrodt-Saaydeh, S.; Graf, B.; Hommel, B.; Jensen, J.; Kiss, J.; Kudsk, P.; et al. Eight principles of integrated pest management. Agron. Sustain. Dev. 2015, 35, 1199–1215. [Google Scholar] [CrossRef]
  9. González-Dugo, V.; Orgaz, F.; Fereres, E. Responses of pepper to deficit irrigation for paprika production. Sci. Hort. 2007, 114, 77–82. [Google Scholar] [CrossRef]
  10. Delfine, S.; Tognetti, R.; Loreto, F.; Alvino, A. Physiological and growth responses to water stress in field-grown bell pepper (Capsicum annuum L.). J. Hort. Sci. Biotechnol. 2002, 77, 697–704. [Google Scholar] [CrossRef]
  11. Singandhupe, R.B.; Rao, G.G.S.N.; Patil, N.G.; Brahmanand, P.S. Fertigation studies and irrigation scheduling in drip irrigation system in tomato crop (Lycopersicon esculentum L.). Eur. J. Agron. 2003, 19, 327–340. [Google Scholar] [CrossRef]
  12. Maisiri, N.; Senzanje, A. On farm evaluation of the effect of low cost drip irrigation on water and crop productivity compared to conventional surface irrigation system. Phys. Chem. Earth 2005, 30, 783–791. [Google Scholar] [CrossRef]
  13. Barkunan, S.R.; Bhanumathi, V.; Sethuram, J. Smart sensor for automatic drip irrigation system for paddy cultivation. Comput. Electr. Eng. 2019, 73, 180–193. [Google Scholar] [CrossRef]
  14. Das, S.; Rahman, M.; Dash, P.K.; Kamal, M. Suppression of chili leaf curl virus (ChLCV) incidence in chili (Capsicum annuum L.) across Bangladesh via manipulated planting date and spacing. J. Plant Dis. Prot. 2021, 128, 535–548. [Google Scholar] [CrossRef]
  15. Setiawati, W.; Muharam, A.; Hasyim, A.; Prabaningrum, L.; Moekasan, T.K.; Murtiningsih, R.; Lukman, L.; Mejaya, M.J. Growth, yield characters and pest and diseases severity of chili pepper under different plant density and pruning levels. Appl. Ecol. Environ. Res. 2022, 20, 543–553. [Google Scholar] [CrossRef]
  16. Boateng, E.; Adjei, E.A.; Osei, M.K.; Offei, K.O.; Olympio, N.S. Response of plant spacing on the morphology and yield of five hot pepper lines. Afr. J. Agric. Res. 2021, 7, 1281–1287. [Google Scholar] [CrossRef]
  17. Morse, J.G.; Hoddle, M.S. Invasion biology of thrips. Ann. Rev. Entomol. 2006, 51, 67–89. [Google Scholar] [CrossRef] [PubMed]
  18. ThripsWiki. ThripsWiki-Providing Information on the World’s Thrips. Available online: http://thrips.info/wiki/ (accessed on 29 June 2022).
  19. Maharijaya, A.; Vosman, B.; Steenhuis-Broers, G.; Harpenas, A.; Purwito, A.; Visser, R.G.F.; Voorrips, R.E. Screening of pepper accessions for resistance against two thrips species (Frankliniella occidentalis and Thrips parvispinus). Euphytica 2011, 177, 401–410. [Google Scholar] [CrossRef]
  20. Roggero, P.; Pennazio, S.; Masenga, V.; Tavella, L. Resistance to tospoviruses in pepper. In Proceedings of the 7th International Symposium on Thysanoptera, Thrips and Tospoviruses, Reggio Calabria, Italy, 2–7 July 2001; Marullo, R., Mound, L., Eds.; pp. 105–110. [Google Scholar]
  21. Whitfield, A.E.; Ullman, D.E.; German, T.L. Tospovirus–thrips interactions. Ann. Rev. Phytopathol. 2005, 43, 459–489. [Google Scholar] [CrossRef]
  22. Lewis, T.; Mound, L.A.; Nakahara, S.; Childers, C.C. Major crops infested by thrips with main symptoms and predominant injurious species. In Thrips as Crop Pests, 1st ed.; Lewis, T., Ed.; CAB Int.: Wallingford, UK, 1997; pp. 675–709. [Google Scholar]
  23. Reitz, S.R.; Yearby, E.L.; Funderburk, J.E.; Stavisky, J.; Momol, M.T.; Olson, S.M. Integrated management tactics for Frankliniella Thrips (Thysanoptera: Thripidae) in field-grown pepper. J. Econ. Entomol. 2003, 96, 1201–1214. [Google Scholar] [CrossRef]
  24. Cannon, R.J.C.; Matthews, L.; Collins, D.W. A review of the pest status and control options for Thrips palmi. Crop Prot. 2007, 26, 1089–1098. [Google Scholar] [CrossRef]
  25. Sahu, P.S.; Kumar, A.; Khan, H.H.; Naz, H. Seasonal incidence of chilli thrips, Scirtothrips dorsalis (Hood) (Thripidae: Thysanoptera): A review. J. Entomol. Zool. Stud. 2018, 6, 1738–1740. [Google Scholar]
  26. Jenser, G. A checklist of Thysanoptera of Hungary. Folia Entomol. Hung. 2011, 72, 31–46. [Google Scholar]
  27. zur Strassen, R. Die terebranten Thysanopteren Europas und des Mittelmeer-Gebietes. Die Tierwelt Deutschlands 74, 1st ed.; Verlag Goecke & Evers: Keltern, Germany, 2003; Volume 74, p. 46. [Google Scholar]
  28. Jenser, G. Tripszek—Thysanoptera. In Magyarország Állatvilága, Fauna Hungariae, 1st ed.; Academic Press: Budapest, Hungary, 1982; Volume 13, p. 19. [Google Scholar]
  29. Czencz, K.; Jenser, G. Microhabitats of Aeolothrips intermedius BAGNALL 1934 (Thysanoptera: Aeolothripidae). Cour. Forschungsinst. Senckenberg. 1994, 178, 51–55. [Google Scholar]
  30. Trdan, S.; Andjus, L.; Raspudić, E.; Kač, M. Distribution of Aeolothrips intermedius Bagnall (Thysanoptera: Aeolothripidae) and its potential prey Thysanoptera species on different cultivated host plants. J. Pest. Sci. 2005, 78, 217–226. [Google Scholar] [CrossRef]
  31. Trdan, S.; Rifelj, M.; Valič, N. Population dynamics of banded thrips (Aeolothrips intermedius Bagnall, Thysanoptera, Aeolothripidae) and its potential prey Thysanoptera species on white clover. Comm. App. Biol. Sci. Ghent Univ. 2005, 70, 753–758. [Google Scholar]
  32. Baez, I.; Reitz, S.R.; Funderburk, J.E.; Reitz, S.R.; Funderburk, J.E. Predation by Orius insidiosus (Heteroptera: Anthocoridae) onlife stages and species of Frankliniella flower thrips (Thysanoptera: Thripidae) in pepper flowers. Environ. Entomol. 2004, 33, 662–670. [Google Scholar] [CrossRef]
  33. Sabelis, M.W.; Van Rijn, P.C.J. Predation by insects and mites. In Thrips as Crop Pests, 1st ed.; Lewis, T., Ed.; CAB International: Wallingford, UK, 1997; pp. 259–354. [Google Scholar]
  34. Funderburk, J.; Stavisky, J.; Olson, S. Predation of Frankliniella occidentalis (Thysanoptera: Thripidae) in field peppers by Orius insidiosus (Hemiptera: Anthocoridae). Environ. Entomol. 2000, 29, 376–382. [Google Scholar] [CrossRef]
  35. Ramachandran, S.; Funderburk, J.; Stavisky, J.; Olson, S. Population abundance and movement of Frankliniella species and Orius insidiosus in field pepper. Agric. Forest Entomol. 2001, 3, 1–10. [Google Scholar] [CrossRef]
  36. Loomans, A. Parasitoids as Biological Control Agents of Thrips Pests. Ph.D. Thesis, Wageningen University, Wageningen, The Netherlands, 2003. [Google Scholar]
  37. Blümel, S.; Fischer-Colbrie, P.; Höbaus, E. Nützlinge: Helfer im zeitgemässen Pflanzenschutz, 3rd ed.; Verlag Jugend & Volk Ges.m.b.H.: Wien, Austria, 1988; p. 111. [Google Scholar]
  38. Rácz, V. Poloskák (Heteroptera) Szerepe Magyarországi Kukoricások Életközösségében. Master’s Thesis, Hungarian Academy of Science, Budapest, Hungary, 1989. [Google Scholar]
  39. O’Keefe, D.A.; Palada, M.C. In-row plant spacing affects growth and yield of four hot pepper cultivars. In Proceedings of the Caribbean Food Crops Society, 38th Annual Meeting, Trois-Ilets, Martinique, France, 30 June–5 July 2002; Merlini, X., Jean-Baptiste, I., Mbolidi-Baron, H., Eds.; AMADEPA: Martinique, France; pp. 162–168. [Google Scholar]
  40. Karungi, J.; Obua, T.; Kyamanywa, S.; Mortensen, C.N.; Erbaugh, M. Seedling protection and field practices for management of insect vectors and viral diseases of hot pepper (Capsicum chinense Jacq.) in Uganda. Int. J. Pest. Manag. 2013, 59, 103–110. [Google Scholar] [CrossRef]
  41. Werner, J. Capsaicinoids—Properties and mechanisms of pro-health action. In Analytical Methods in the Determination of Bioactive Compounds and Elements in Food. Food Bioactive Ingredients; Jeszka-Skowron, M., Zgoła-Grześkowiak, A., Grześkowiak, T., Ramakrishna, A., Eds.; Springer: Cham, Switzerland, 2021; pp. 193–225. [Google Scholar] [CrossRef]
  42. Bosland, P.W.; Coon, D.; Reeves, G. ‘Trinidad Moruga Scorpion’ pepper is the world’s hottest measured chile pepper at more than two million Scoville heat units. Horttechnology 2012, 22, 534–538. [Google Scholar] [CrossRef]
  43. Trinidad Scorpion Butch, T. Available online: https://pepperhead.com/shop/trinidad-scorpion-butch-t/ (accessed on 25 July 2022).
  44. Maguire, K. Red Hot Chilli Grower, 1st ed.; Mitchell Beazley: London, UK, 2015; p. 110. [Google Scholar]
  45. R Core Team. R: A Language and Environment for Statistical Computing; R Foundation for Statistical Computing: Vienna, Austria, 2021; Available online: https://www.R-project.org/ (accessed on 20 January 2022).
  46. Fox, J. Using the R Commander: A Point-and-Click Interface for R; Chapman & Hall/CRC: Boca Raton, FL, USA, 2017; pp. 1–233. [Google Scholar]
  47. Faraway, J.J. Linear Models with R, 2nd ed.; Chapman & Hall/CRC: Boca Raton, FL, USA, 2014; pp. 1–270. [Google Scholar]
  48. Lewis, T. Thrips. Their Biology, Ecology and Economic Importance; Academic Press: London, UK, 1973; pp. 187–201. [Google Scholar]
  49. Maris, P.C.; Joosten, N.N.; Peters, D.; Goldbach, R.W. Thrips resistance in pepper and its consequences for the acquisition and inoculation of Tomato spotted wilt virus by the Western Flower Thrips. Phytopathology 2003, 93, 96–101. [Google Scholar] [CrossRef]
  50. Van Haperen, P.; Voorrips, R.E.; van Loon, J.J.A.; Vosman, B. The effect of plant development on thrips resistance in Capsicum. Arthropod Plant Interact. 2019, 13, 11–18. [Google Scholar] [CrossRef]
  51. Syamsudin, T.S.; Faizal, A.; Kirana, R. Dataset on antixenosis and antibiosis of chili fruit by fruit fly (Bactrocera dorsalis) infestation. Data Brief 2019, 23, 103758. [Google Scholar] [CrossRef] [PubMed]
  52. Syamsudin, T.S.; Kirana, R.; Karjadi, A.K.; Faizal, A. Characteristics of chili (Capsicum annuum L.) that are resistant and susceptible to oriental fruit fly (Bactrocera dorsalis Hendel) infestation. Horticulturae 2022, 8, 314. [Google Scholar] [CrossRef]
  53. Fery, R.L.; Thies, J.A. Evaluation of Capsicum chinense Jacq. Cultigens for resistance to the Southern Root-knot Nematode. Hort. Sci. 1997, 32, 923–926. [Google Scholar] [CrossRef]
  54. Kirk, W.D.J. Distribution, Abundance and Population Dynamics. In Thrips as Crop Pests; Lewis, T., Ed.; CAB Int.: Wallingford, UK, 1997; pp. 217–257. [Google Scholar]
  55. de Pedro, L.; López-Gallego, E.; Pérez-Marcos, M.; Ramírez-Soria, M.J.; Sanchez, J.A. Native natural enemies in Mediterranean melon fields can provide levels of pest control similar to conventional pest management with broad-spectrum pesticides. Biol. Control 2021, 164, 104778. [Google Scholar] [CrossRef]
  56. Fok, E.J.; Petersen, J.D.; Nault, B.A. Relationships between insect predator populations and their prey, Thrips tabaci, in onion fields grown in large-scale and small-scale cropping systems. BioControl 2014, 59, 739–748. [Google Scholar] [CrossRef]
  57. El-Serwiy, S.A.; Razoki, I.A.; Ragab, A.S. Population density of Thrips tabaci (Lind.) and the predators Orius albidipennis (Reut.) and Aeolothrips fasciatus (L.) on onion. J. Agric. Water Resour. Res. 1985, 4, 57–67. [Google Scholar]
  58. Fathi, S.A.A.; Asghari, A.; Sedghi, M. 2008. Interaction of Aeolothrips intermedius and Orius niger in controlling Thrips tabaci on potato. Int. J. Agri. Biol. 2008, 10, 521–525. [Google Scholar]
  59. Abdala-Roberts, L.; Berny-Mier y Terán, J.C.; Moreira, X.; Durán-Yáñez, A.; Tut-Pech, F. Effects of pepper (Capsicum chinense) genotypic diversity on insect herbivores. Agric. Forest Entomol. 2015, 17, 433–438. [Google Scholar] [CrossRef]
Horticulturae 08 00741 g001 550
Figure 1. Daily maximum (Max.), minimum (Min.), and average (Av.) air temperature and rainfall (RF) data for the growing seasons 2019 and 2021.
Figure 1. Daily maximum (Max.), minimum (Min.), and average (Av.) air temperature and rainfall (RF) data for the growing seasons 2019 and 2021.
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Figure 2. Average individual numbers of predatory and phytophagous insects in chili flowers under treatments in 2019: (A) Orius spp. (B) Phytophagous thrips. (C) All Orius and phytophagous thrips (adults and larvae). (D) Aeolothrips spp. (V1) Trinidad Scorpion Butch T; (V2) Yellow Scotch Bonnet; (I1) Irrigation daily, 40 min; (I2) Irrigation every second day, 20 min; (PS1) Increased plant spacing; (PS2) Decreased plant spacing. * Denotes significant differences between the treatment levels (p < 0.001). The error bars represent the standard errors.
Figure 2. Average individual numbers of predatory and phytophagous insects in chili flowers under treatments in 2019: (A) Orius spp. (B) Phytophagous thrips. (C) All Orius and phytophagous thrips (adults and larvae). (D) Aeolothrips spp. (V1) Trinidad Scorpion Butch T; (V2) Yellow Scotch Bonnet; (I1) Irrigation daily, 40 min; (I2) Irrigation every second day, 20 min; (PS1) Increased plant spacing; (PS2) Decreased plant spacing. * Denotes significant differences between the treatment levels (p < 0.001). The error bars represent the standard errors.
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Figure 3. Average individual numbers of predatory and phytophagous insects in chili flowers under treatments in 2021: (A) Orius spp. (B) Phytophagous thrips. (C) All Orius and phytophagous thrips (adults and larvae). (D) Aeolothrips spp. (V1)Trinidad Scorpion Butch T; (V2) Yellow Scotch Bonnet; 230 (I1) Irrigation daily, 40 min; (I2) Irrigation every second day, 20 min; (PS1) Increased plant spacing; (PS2) Decreased plant spacing. * Denotes significant differences between the treatment levels (p < 0.001). The error bars represent the standard errors.
Figure 3. Average individual numbers of predatory and phytophagous insects in chili flowers under treatments in 2021: (A) Orius spp. (B) Phytophagous thrips. (C) All Orius and phytophagous thrips (adults and larvae). (D) Aeolothrips spp. (V1)Trinidad Scorpion Butch T; (V2) Yellow Scotch Bonnet; 230 (I1) Irrigation daily, 40 min; (I2) Irrigation every second day, 20 min; (PS1) Increased plant spacing; (PS2) Decreased plant spacing. * Denotes significant differences between the treatment levels (p < 0.001). The error bars represent the standard errors.
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Figure 4. Seasonal dynamics of predatory and phytophagous insects in chili pepper flowers in 2019. (A) Trinidad Scorpion Butch T. (B) Yellow Scotch Bonnet. (C) Irrigation daily, 40 min. (D) Irrigation every second day, 20 min. (E) Increased plant spacing. (F) Decreased plant spacing. The error bars represent the standard errors.
Figure 4. Seasonal dynamics of predatory and phytophagous insects in chili pepper flowers in 2019. (A) Trinidad Scorpion Butch T. (B) Yellow Scotch Bonnet. (C) Irrigation daily, 40 min. (D) Irrigation every second day, 20 min. (E) Increased plant spacing. (F) Decreased plant spacing. The error bars represent the standard errors.
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Figure 5. Seasonal dynamics of predatory and phytophagous insects in chili pepper flowers in 2021. (A) Trinidad Scorpion Butch T. (B) Yellow Scotch Bonnet. (C) Irrigation daily, 40 min. (D) Irrigation every second day, 20 min. (E) Increased plant spacing. (F) Decreased plant spacing. The error bars represent the standard errors.
Figure 5. Seasonal dynamics of predatory and phytophagous insects in chili pepper flowers in 2021. (A) Trinidad Scorpion Butch T. (B) Yellow Scotch Bonnet. (C) Irrigation daily, 40 min. (D) Irrigation every second day, 20 min. (E) Increased plant spacing. (F) Decreased plant spacing. The error bars represent the standard errors.
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Table
Table 1. Total insect numbers in chili flowers during growing seasons.
Table 1. Total insect numbers in chili flowers during growing seasons.
YearAeolothrips AdultsAeolothrips LarvaeOrius AdultsOrius LarvaePhytophagous Thrips AdultsPhytophagous Thrips Larvae
2019103116146877512213
202114441705742931030
Table
Table 2. Effects of variety, irrigation level and plant spacing on the insect abundance of chili flowers in 2019. Residual degrees of freedom were 138 in all tests.
Table 2. Effects of variety, irrigation level and plant spacing on the insect abundance of chili flowers in 2019. Residual degrees of freedom were 138 in all tests.
VarietyIrrigationPlant Spacing
Insect TaxaEffect EstimateTest Statisticsp ValueEffect EstimateTest Statisticsp ValueEffect EstimateTest Statisticsp Value
Phytophagous thrips adults2.8307F = 0.88760.4160−8.2857F = 8.06240.00991.3333F = 0.41390.7030
Phytophagous thrips larvae0.5589χ2 = 0.28660.8660−0.3571χ2 = 0.11740.3950−0.2717χ2 = 0.06770.4005
All phytophagous thrips3.3897F = 1.13280.2189−8.6428F = 7.86290.00911.0615F = 0.28040.6013
Orius adults−3.4769χ2 = 16.190<0.0010.7142χ2 = 0.68550.40800.3179χ2 = 0.13480.7130
Orius larvae−7.8717F = 0.01490.0135−3.78572F = 0.29150.4460−1.7487F = 0.24300.7550
All Orius−11.3487F = 12.54630.0011−3.0714F = 0.50300.4460−1.4307F = 0.14340.7550
Aeolothrips adults0.4051χ2 = 0.31170.5810−3.0714χ2 = 18.513<0.0010.7435χ2 = 1.04350.3080
Aeolothrips larvae0.1230χ2 = 0.02550.8100−0.8571χ2 = 1.24360.22600.8820χ2 = 1.30370.2210
All Aeolothrips0.5282χ2 = 0.24890.4441−3.9285χ2 = 13.962<0.0011.6256χ2 = 2.34570.0714
Table
Table 3. Effects of variety, irrigation level and plant spacing on the insect abundance in chili flowers in 2021. Residual degrees of freedom were 178 in all tests.
Table 3. Effects of variety, irrigation level and plant spacing on the insect abundance in chili flowers in 2021. Residual degrees of freedom were 178 in all tests.
VarietyIrrigationPlant Spacing
Insect TaxaEffect EstimateTest Statisticsp ValueEffect EstimateTest Statisticsp ValueEffect EstimateTest Statisticsp Value
Phytophagous thrips adults0.7678χ2 = 0.45170.3620−0.3333χ2 = 0.08530.78500.6339χ2 = 0.30780.4220
Phytophagous thrips larvae−5.0625F = 1.52480.438310.8000F = 6.97040.02664.5803F = 1.06430.2829
All phytophagous thrips−4.2946F = 1.14720.619810.4666F = 6.84420.05615.2142F = 1.50560.2637
Orius adults0.4464χ2 = 0.26310.5150−1.6000χ2 = 3.39960.06080.0446χ2 = 0.00260.8250
Orius larvae−0.6875F = 0.16740.7960−0.2666F = 0.02530.8530−2.5625F = 2.42760.1770
All Orius−0.2411F = 0.01700.9330−1.8666F = 1.02330.3000−2.5178F = 1.88860.2800
Aeolothrips adults−0.1964χ2 = 0.61610.4240−0.1333χ2 = 0.28670.5820−0.1964χ2 = 0.61610.4240
Aeolothrips larvae0.5267χ2 = 1.3390.20980.3333χ2 = 0.53290.45520.1250χ2 = 0.07460.6571
All Aeolothrips0.3303χ2 = 0.40270.47070.2000χ2 = 0.14760.6950−0.0714χ2 = 0.01870.9959
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Juhász, A.L.; Szalai, M.; Szénási, Á. Assessing the Impact of Variety, Irrigation, and Plant Distance on Predatory and Phytophagous Insects in Chili. Horticulturae 2022, 8, 741. https://doi.org/10.3390/horticulturae8080741

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Juhász AL, Szalai M, Szénási Á. Assessing the Impact of Variety, Irrigation, and Plant Distance on Predatory and Phytophagous Insects in Chili. Horticulturae. 2022; 8(8):741. https://doi.org/10.3390/horticulturae8080741

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Juhász, András Lajos, Márk Szalai, and Ágnes Szénási. 2022. "Assessing the Impact of Variety, Irrigation, and Plant Distance on Predatory and Phytophagous Insects in Chili" Horticulturae 8, no. 8: 741. https://doi.org/10.3390/horticulturae8080741

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