Junwei Zhu

Biosecurity is an increasingly important aspect of management of commodities in a globalised economy. The larger grain borer, Prostephanus truncatus , is a known biosecurity threat to the United States and has been classified as a species‐of‐concern. Under climate change, P. truncatus is expected to expand its range into the United States from Mexico. In this study, we performed a 2‐year latitudinal biosurveillance programme for P. truncatus , related bostrichids and Sitophilus spp. as key species in and around maize and wheat production at 10–15 sites from 20° to 47° latitude in North America and Greece to evaluate how habitat, latitude and season affected spatiotemporal dynamics of these insects. Two types of traps, a 4‐funnel Lindgren and pitfall traps, were deployed at each site, baited with each species' pheromones. In total, we captured 2528 insects in 2021 and 29,080 insects in 2022. P. truncatus was only documented in Mexico but in high abundance in both years. Interestingly, even though P. truncatus is a good flier, the funnel trap was equally effective as the pitfall trap in monitoring P. truncatus . Conspecifics were found most often in natural and row crop habitats in both years compared to food facilities. Captures of P. punctatus in 2022 most often occurred in natural habitats, but they were still present at row crops and near food facilities. By contrast, Sitophilus spp. were most associated with food facilities. Overall, this study helps inform current risk from P. truncatus and fundamental patterns of spatiotemporal distribution for several related key stored product insects.

Previous studies have shown oviposition deterring properties of 8 coconut free fatty acid (CFFA) compounds on fruit flies with different key deterrent components for different species. Here we evaluated oviposition deterrence of CFFA using laboratory 2‐choice bioassays against Zeugodacus cucurbitae, determined key‐bioactive deterrent compounds, and evaluated their behavioral mode. Unlike other reported fruit fly species, CFFA mixture increased Z. cucurbitae oviposition when directly applied on an oviposition substrate. When tested individually in subsequent tests, 4 compounds (caprylic, capric, oleic, and linoleic acids) significantly reduced the oviposition (“negative‐compounds”), 1 compound (stearic acid) had no effect (“neutral‐compound”), and 3 compounds (lauric, myristic, and palmitic acids) stimulated the oviposition (“positive‐compounds”). The 4‐component negative‐compound blend was effective at reducing oviposition. However, adding stearic acid to the 4‐component blend (5‐component blend, 5c) further reduced oviposition. Adding any of the positive‐compounds to the 5c resulted in loss of oviposition deterrence, suggesting the 5c as the key deterrent component blend. The blend was also effective in no‐choice assays and when applied on cucumbers, a preferred host of Z. cucurbitae. When given a choice, Z. cucurbitae made 48.5% fewer visits, spent 39% less time, and oviposited 88.2% fewer eggs per min on 5c treated pumpkin agar than on control agar, suggesting that the 5c blend has both spatial repellency and contact deterrence. Given that all compounds are registered food additives and generally regarded as safe, this blend has potential application in behavioral control strategies, such as push–pull, to protect host fruit against Z. cucurbitae.

BACKGROUND: Stable flies [Stomoxys calcitrans (L.)] are economically important pests of cattle and other livestock. As an alternative to conventional insecticides, we tested a push–pull management strategy using a coconut oil fatty acid repellent formulation and an attractant‐added stable fly trap.RESULTS: In our field trials we found that weekly applications of a push–pull strategy can reduce stable fly populations on cattle as well as a standard insecticide (permethrin). We also found that the efficacy periods of the push–pull and permethrin treatments following on‐animal application were equivalent. Traps with an attractant lure used as the pull component of the push–pull strategy captured sufficient numbers of stable flies to reduce on‐animal numbers by an estimated 17–21%.CONCLUSIONS: This is the first proof‐of‐concept field trial demonstrating the effectiveness of a push–pull strategy using a coconut oil fatty acid‐based repellent formulation and traps with an attractant lure to manage stable flies on pasture cattle. Also notable is that the push–pull strategy had an efficacy period equivalent to that of a standard, conventional insecticide under field conditions. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Reactive power optimization is to minimize the active power losses of the distribution network by coordinating on-load tap-changing(OLTC) transformer and reactive power compensation(RPC) equipment, such as capacitor banks(CB) and static var compensator(SVC), etc.. Aside from power losses, minimizing voltage deviation is also an important aspect of reactive power optimization. Traditional reactive power optimization only considers the optimization effect of a single period, not the overall day's optimization. In view of this, a multi-objective dynamic reactive power optimization model is established in this paper, with the objective of minimizing the active power losses and voltage deviation, and the constraints of OLTC and RPC equipment. The second-order cone relaxation (SOCR) is used to convert the mixed integer nonlinear programming (MINLP) problem into the mixed integer second-order cone programming (MISOCP) problem, and the multi-objective variable-weight method is adapted to achieve the multi-objective dynamic reactive power optimization. Case studies are carried out on the modified IEEE 33-node system to verify the feasibility and effectiveness of the proposed method.

Stable flies are one of the most important arthropod pests of livestock that reduce cattle weight gain and milk production leading to annual economic losses in excess of $2 billion to the US cattle industry. The host-seeking behavior is primarily mediated by associated odors from stable fly larval development environments and host animals. The present paper reports the development and evaluation of attractant-impregnated adhesive tapes to reduce stable fly attacks on cattle. Laboratory bioassays showed that only m-cresol impregnated adhesive tapes caught significantly more stable flies (16 +/- 1) than the control tape without attractant added (7 +/- 1), with a 77% fly recapture rate. Attractant-impregnated adhesive tapes deployed in cattle feedlots showed significant impacts in reducing fly population, with a total of one million stable flies captured over a period of three weeks (mean catches from 57 596 to 102 088 stable flies per trap per week). It further relieved cattle stress with a significant reduction of biting fly avoidance behavior, (6 +/- 0.4 cows observed with tail wagging in control vs. 3 +/- 0.4 from the trap-deployed). The efficacy of the developed tapes lasted up to 1-week longevity, although 70% of m-cresol was released starting from the second day. The m-cresol impregnated adhesive tape provided an 80% reduction in cattle stress due to stable fly attack. This is the first report of a technology developed by integrating an attractant compound into an adhesive material on a plastic film with demonstrated effectiveness in trapping biting flies that attack livestock animals.

The antimicrobial activities of (Z,E)- and (E,Z)-nepetalactones, 2 major compositional compounds from the essential oil of catnip (Nepeta cataria), were first discovered from fly larval development media studies with over 98% inhibition of bacterial growth. Further investigation demonstrated inhibition of the growth of various bacterial species of public health significance. Catnip oil showed antibacterial activity against 5 Gram-positive and 9 Gram-negative bacteria. The antimicrobial activity varied among the original essential oil from the plant and its major compositional compounds as a blended mixture or an individual compound. Growth inhibition was observed against 5 Neisseria species, with particularly strong inhibition against Neisseria sicca (with MICs ranging from 0.5 to 5 mg/mL) that provided comparable or increased levels of growth control produced by 2 antibiotics (Ceftiofur and Cephalothin). The development of plant-based antibacterial agents to prevent or delay the emergence of antimicrobial resistance in bacteria is discussed.