Search Results (6)

This study investigated the abundance and richness of insect pests and beneficial insects on 20 squash cultivars across three seasons in middle Georgia, U.S. Insects were sampled using yellow sticky cards, pan traps and sweep nets. Bemisia tabaci Gennadius (sweet potato whitefly) was prevalent in all seasons, while other key pests showed distinct seasonal peaks. Diaphania hyalinata Linnaeus (melonworm) peaked mid-July in summer 2021 (21 June–1 August), while Thysanoptera species, Acalymma vittatum Fabricius (striped cucumber beetle), and Diabrotica balteata LeConte (banded cucumber beetle) peaked late July-early August. In fall 2021 (4 October–14 November), Epilachna borealis (squash beetle), D. hyalinata, and D. nitidalis Stoll (pickleworm) were more active in early to mid-October, whereas D. undecimpunctata howardi Barber (spotted cucumber beetle) peaked in late November. In fall 2022 (17 October–20 November), D. balteata and D. undecimpunctata howardi peaked mid October to early November, while Anasa tristis DeGeer (squash bug) peaked in mid–late November. Orius insidiosus Say (minute pirate bug) peaked in late summer 2021 and remained stable in fall 2021. Pollinators were most active in mid-fall. Cultivars influenced insect abundance. ‘Saffron’ and ‘Amberpic 8455’ harbored the most O. insidiosus and fewer D. balteata and Thysanoptera species. ‘Golden Goose Hybrid’ had the highest moth numbers. These patterns suggest that cultivar traits influenced pest susceptibility and beneficial arthropods’ activity. Temperature and relative humidity were positively correlated with A. vittatum and E. borealis numbers, but rainfall negatively affected bees. These findings underscore the importance of cultivar selection and weather condition considerations in integrated pest management. Full article

Bitter Hawkesbury watermelon (BHW) Citrullus lanatus (Thunb.) Matsum. and Nakai (syn. Citrullus vulgaris Schad) contain high concentrations of cucurbitacin-E-glycoside (CEG), a compound that acts as an arrestant and feeding stimulant for diabroticine leaf beetles that are corn (maize) and cucurbit pests. Juice from BHW is used as feedstock to produce an insecticide synergist for improved chemical control of pests in cucurbit cropping systems. A positive linear relationship was observed between the CEG concentration of parent and offspring grown in open-pollinated field plots. However, subsequent experiments that explored the influence of parent and fruit maturity on CEG concentration did not confirm a relationship between accumulation patterns among offspring of half-sibling families. An effect of maturity was observed in that earlier harvested fruit had greater CEG concentrations than ripe or overripe fruit. In a field study, CIDETRAK L (active ingredient is BHW juice) was mixed with commonly used insecticides to enhance behavioral control of striped cucumber beetle Acalymma vittatum (F.) and squash vine borer Melittia cucurbitae (Harris). Equivalent control of A. vittatum and M. cucurbitae was observed on zucchini when treated with foliar applications of spinosad, acetamiprid, or lambda-cyhalothrin versus ground applications of the same products mixed with CIDETRAK L. Full article

The striped cucumber beetle (SCB) Acalymma vittatum (F.) (Coleptera: Chrysomelidae) is a prime problem in North American cucurbit crops. While certain chemical pesticides efficiently control SCB in conventional cucurbit fields, alternative solutions are required due to the ever-evolving regulations on pesticides. For organic producers, very few control methods exist. A novel mass trapping method demonstrates the potential of controlling SCBs using floral-based semiochemical baited traps in cucurbit crops. The goals of this study were to (1) determine whether baited traps capture more SCBs than unbaited ones, and (2) optimize the trapping method by comparing different trap types and different commercially available attractants to maximize SCB captures while minimizing non-target species captures. The results of a first experiment showed that baited traps captured significantly more SCBs than unbaited ones. Baited traps also captured significantly more bees and hoverflies than unbaited ones. In a second experiment these unwanted captures were drastically reduced by using traps with ten 4 mm in diameter holes per side. Finally, a third experiment demonstrated that the attractant 40CT313 was the most efficient at capturing SCB compared to other tested lures. Overall, the optimized mass trapping technique demonstrated a potential to effectively control SCB populations in organic cucurbit crops. Full article

Plants allocate their limited resources toward different physiological processes, dynamically adjusting their resource allocation in response to environmental changes. How beneficial plant-associated microbes influence this allocation is a topic that continues to interest plant biologists. In this study, we examined the effect of a beneficial fungus, Phialemonium inflatum, on investment in growth and anti-herbivore resistance traits in cucumber plants (Cucumis sativus). We inoculated cucumber seeds with P. inflatum spores and measured several growth parameters, including germination rate, above and belowground biomass, and number of flowers. We also examined plant resistance to adult and larval striped cucumber beetles (Acalymma vitattum), and quantified levels of defense hormones in leaves and roots. Our results indicate that P. inflatum strongly enhances cucumber plant growth and reproductive potential. Although fungus treatment did not improve plant resistance to cucumber beetles, inoculated plants were more tolerant to root herbivory, experiencing less biomass reduction. Together, these findings document how a beneficial plant-associated fungus shifts plant investment in growth over herbivore resistance, highlighting the importance of microbes in mediating plant-herbivore interactions. These findings also have important implications for agricultural systems, where beneficial microbes are often introduced or managed to promote plant growth or enhance resistance. Full article

Acalymma vittatum (F.), the striped cucumber beetle, is an important pest of cucurbit crops in the contintental United States, damaging plants through both direct feeding and vectoring of a bacterial wilt pathogen. Besides providing basic biological knowledge, biosequence data for A. vittatum would be useful towards the development of molecular biopesticides to complement existing population control methods. However, no such datasets currently exist. In this study, three biological replicates apiece of male and female adult insects were sequenced and assembled into a set of 630,139 transcripts (of which 232,899 exhibited hits to one or more sequences in NCBI NR). Quantitative analyses identified 2898 genes differentially expressed across the male–female divide, and qualitative analyses characterized the insect’s resistome, comprising the glutathione S-transferase, carboxylesterase, and cytochrome P450 monooxygenase families of xenobiotic detoxification genes. In summary, these data provide useful insights into genes associated with sex differentiation and this beetle’s innate genetic capacity to develop resistance to synthetic pesticides; furthermore, these genes may serve as useful targets for potential use in molecular-based biocontrol technologies. Full article

Plant varieties resistant to insect pests are a critical component of integrated pest management, but challenges associated with plant breeding for insect resistance, such as a long breeding cycle duration and low trait heritability, slow progress in the field. In this study, we tested two novel selection schemes to improve genetic gain for resistance to the major pest, the striped cucumber beetle (Acalymma vittatum), in squash (Cucurbita pepo, e.g., zucchini). First, we tested an indirect selection scheme using a proxy insect with correlated resistance phenotypes, Trichoplusia ni, in place of the seasonally available A. vittatum. We found that while resistance to herbivory by T. ni was heritable, there was no reciprocal benefit for resistance to A. vittatum. Second, we tested genomic selection, a method that allows for selection without phenotyping every generation, for both resistance to A. vittatum directly and resistance to the proxy T. ni. Although there was moderate genomic predictive ability, we did not observe realized gains from selection in field trials. Overall, strategies that minimize investment in direct phenotyping, leverage efficiencies from phenotyping correlated traits, and shorten breeding cycle duration are needed to develop insect resistant varieties, and this study provides examples and empirical data of two such approaches deployed in an applied breeding program. Full article