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Plants have limited resources to allocate to defences against infection and herbivory. While interactions between plant responses to microbial and herbivore attack are complex, it is often the case that the induction of one response will act antagonistically to the other. Recent studies have shown that plant growth promoting rhizobacteria, which improves overall plant health and general stress resistance, can enhance both anti-microbial and anti-herbivore defences. We investigated how soil application of the biofungicide Serenade ASO (Bacillus subtilis strain QST 713), which primes plant defences against fungal and bacterial infection and promotes plant growth, affects anti-herbivore defences by measuring both constitutive and induced defences. We applied Serenade one or two times to the soil of tomato plants and measured the numbers of type IV glandular trichomes on leaves, the weight gain of a generalist caterpillar (beet armyworms; BAW), and the activity of two enzymes associated with defence against insects (polyphenoloxidase and peroxidase). Serenade treated plants grew faster and foliage from treated plants had significantly higher numbers of glandular trichomes and higher polyphenoloxidase and peroxidase activities than untreated plants. However, Serenade treatment did not affect the degree of induction of plant defences when damaged by BAW feeding and did not slow the growth rate of BAW relative to plants not treated with Serenade. Therefore, the biofungicide Serenade increased plant growth and altered the densities of trichomes and the activities of two defensive enzymes in plants, but it did not affect overall susceptibility of the plants to a generalist herbivore. [ABSTRACT FROM AUTHOR]

BACKGROUND: Insecticide resistance among invasive tephritid fruit flies poses a great risk to national food security and has the potential to disrupt quarantine and eradication programs, which rely on the efficacy of Spinosad to prevent widespread establishment in North America. During 2022 to 2023 we surveyed the extent of Spinosad resistance of two key species, oriental fruit fly Bactrocera dorsalis, and melon fly Zeugodacus cucurbitae, from 20 sites across five Hawaiian Islands including Kaua'i, O'ahu, Maui, Molokai and the "Big Island" (Hawai'i). RESULTS: We used topical thoracic applications of eight concentrations of Spinosad ranging from 0.028 to 3.6 mg/mL to evaluate the lethal concentration (LC50 and LC99) required to kill wild‐caught males. Resistance ratios (RR) were calculated by comparing the LC50 of wild flies to laboratory susceptible lines maintained in colony. Our results identified at least two new sites of concern for melon fly resistance on the Big Island, and at least four sites of concern for oriental fruit fly, all of which were located on the Big Island. At these locations RRs were >5. On O'ahu, melon fly RRs were >10. CONCLUSIONS: The persistence of Spinosad resistance is concerning, yet it is a reduction compared to the values reported previously and before changes to Spinosad use recommendations by local extension agents beginning in 2017. For oriental fruit fly, these RR values are the highest levels that have been detected in wild Hawai'i populations. These data suggest that expanded Spinosad reduction and replacement programs are warranted given the ongoing issues with Spinosad resistance in Hawai'i and expansion in the number of species affected. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

Simple Summary: Flies inhabit mushrooms or consume them incidentally throughout their lifecycle. In wild conditions, these flies are part of the recycling process and are not considered pests. However, in commercial mushroom houses, these flies can become problematic, as compost pests, through physical damage of mushroom production through consumption, or as vectors of pathogens or nematodes. Here, we describe the bacterial associates of two fly pest species of Pennsylvania mushroom houses. Mushroom cultivation vastly improves the yield of mushrooms under optimized, controlled conditions, but may be susceptible to opportunistic colonization by pest species that can establish themselves, as well as the pathogens and pests they may transmit. Here, we describe our investigation into the bacterial communities of adult Lycoriella ingenua (Diptera: Sciaridae) and Megaselia halterata (Diptera: Phoridae) collected from button mushroom (Agaricus bisporus) production houses in Pennsylvania. We collected adult flies and sequenced the hypervariable v4 region of the bacterial 16S rRNA using the Illumina MiSeq. The most abundant bacterial genus detected in both species was Wolbachia, but phylogenetic analysis revealed that the infections are from different clades. Future studies include the characterization of Wolbachia infections on fly behavior and biology, comparison of microbial diversity of fly species colonizing wild mushrooms, and other microbiota that may contribute to the success of certain pest fly species. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2008.08.033 Byline: Ikkei Shikano, Murray B. Isman Abstract: We examined the effects of larval feeding experience with a deterrent plant latex on subsequent adult oviposition behaviour in the cabbage looper moth, Trichoplusia ni. Larvae were exposed to the latex of Hoodia gordonii at 100ppm in an artificial diet. This plant material strongly deters oviposition in naA[macron]ve moths in laboratory choice tests. Larvae that were exposed to the latex either for their entire final instar or throughout larval development showed no oviposition deterrence. This effect persisted when larval exposure to H. gordonii latex was suspended for the final 2 days immediately prior to pupation. However, when exposure to latex was suspended for 1 or more days in the beginning of the final instar or for 3 or more days prior to pupation, oviposition behaviour was deterred in subsequent adult moths (i.e. the adults behaved as naA[macron]ve moths). Our observation that adult oviposition choice can be influenced by a change in diet in the final larval instar indicates the presence of a sensitive period whereby larval feeding memory can be lost or maintained in adulthood. Author Affiliation: Faculty of Land and Food Systems, University of British Columbia, Canada Article History: Received 27 February 2008; Revised 23 April 2008; Accepted 7 August 2008 Article Note: (miscellaneous) MS. number: A08-00122R

Insects possess specific immune responses to protect themselves from different types of pathogens. Activation of immune cascades can inflict significant developmental costs on the surviving host. To characterize infection kinetics in a surviving host that experiences baculovirus inoculation, it is crucial to determine the timing of immune responses. Here, we investigated time‐dependent immune responses and developmental costs elicited by inoculations from each of two wild‐type baculoviruses, Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and Helicoverpa zea single nucleopolyhedrovirus (HzSNPV), in their common host H. zea. As H. zea is a semi‐permissive host of AcMNPV and fully permissive to HzSNPV, we hypothesized there are differential immune responses and fitness costs associated with resisting infection by each virus species. Newly molted 4th‐instar larvae that were inoculated with a low dose (LD15) of either virus showed significantly higher hemolymph FAD‐glucose dehydrogenase (GLD) activities compared to the corresponding control larvae. Hemolymph phenoloxidase (PO) activity, protein concentration and total hemocyte numbers were not increased, but instead were lower than in control larvae at some time points post‐inoculation. Larvae that survived either virus inoculation exhibited reduced pupal weight; survivors inoculated with AcMNPV grew slower than the control larvae, while survivors of HzSNPV pupated earlier than control larvae. Our results highlight the complexity of immune responses and fitness costs associated with combating different baculoviruses. [ABSTRACT FROM AUTHOR]

The mushroom phorid fly, Megaselia halterata (Wood), is a common pest of mushroom production in many parts of the world. Due to the reduced availability of conventional insecticides for mushroom production, M. halterata has recently developed into a major pest in the top mushroom-producing county in the United States (Chester County, PA). Mushrooms are grown entirely indoors, and though larval development of M. halterata occurs in the mushroom-growing substrate, adult flies have been captured both inside and outside of the facilities. Here, we investigated three factors that might contribute to their growth and development. 1) The effects of ambient temperature (15–30°C) and relative humidity (RH; 21–98%) on adult M. halterata lifespan, 2) the effect of spawned compost stage (freshly inoculated with spawn vs 14-d spawned compost) on reproductive output, and 3) the effect of population density on reproductive output. The longevity of adult M. halterata increased under cooler temperatures and more humid conditions (>75% RH), which reflect the conditions inside mushroom-growing facilities. Similar numbers of flies emerged from freshly inoculated and 14-d spawned compost, but flies emerged earlier from 14-d spawned compost. The higher the parental fly density, the more offspring emerged from spawned compost, but the positive relationship reached a plateau beyond 40 parental mating pairs per 100 g of compost. Our findings highlight relevant abiotic and biotic factors that may contribute to M. halterata population dynamics. [ABSTRACT FROM AUTHOR]

Rice leaffolder, Cnaphalocrocis medinalis (Lepidoptera: Plutellidae) is an important migratory pest in Asia. While many lepidopteran species are known to enhance adult life history by obtaining supplementary nutrition, little is known about the effects of adult diet on C. medinalis. We first examined the effects of offering five dilutions of honey solution (0%, 5%, 10%, 15% and 20%) on the longevity, fecundity and ovary development of adult C. medinalis. We then compared the effects of 10% honey solution to 25% glucose solution, which was previously reported to be the best adult diet for C. medinalis. We found that adult male and female C. medinalis fed 5%–20% honey solution lived significantly longer than those fed just water. Importantly, a honey–based diet accelerated and increased ovary development and prolonged the oviposition period, leading to higher fecundity. More specifically, females fed 5%–15% honey solution had the highest fecundity, followed by 20% honey solution, and the lowest when fed only water. In addition, the oviposition rate was 100% in females fed 10% and 15% honey solution. When we compared 10% honey solution to 25% glucose solution, those fed honey solution had significantly higher estimated female performance, which is a composite measure consisting of fecundity, percentage of egg‐laying females and percentage of eggs that hatched. Overall, our findings indicate that adult diet quality significantly impacts C. medinalis performance and that using a 10%–15% honey solution is optimal for mass‐rearing under laboratory conditions. [ABSTRACT FROM AUTHOR]

Although the tritrophic interactions of plants, insect herbivores and their natural enemies have been intensely studied for several decades, the roles of entomopathogens in their indirect modulation of plant-insect relationships is still unclear. Here, we employed a sublethal dose of a baculovirus with a relatively broad host range (AcMNPV) to explore if feeding by baculovirus-challenged Helicoverpa zea caterpillars induces direct defenses in the tomato plant. We examined induction of plant defenses following feeding by H. zea, including tomato plants fed on by healthy caterpillars, AcMNPV-challenged caterpillars, or undamaged controls, and subsequently compared the transcript levels of defense related proteins (i.e., trypsin proteinase inhibitors, peroxidase and polyphenol oxidase) and other defense genes (i.e., proteinase inhibitor II and cysteine proteinase inhibitor) from these plants, in addition to comparing caterpillar relative growth rates. As a result, AcMNPV-challenged caterpillars induced the highest plant anti-herbivore defenses. We examined several elicitors and effectors in the secretions of these caterpillars (i.e., glucose oxidase, phospholipase C, and ATPase hydrolysis), which surprisingly did not differ between treatments. Hence, we suggest that the greater induction of plant defenses by the virus-challenged caterpillars may be due to differences in the amount of these secretions deposited during feeding or to some other unknown factor(s). [ABSTRACT FROM AUTHOR]