Field resistance to spinosad in western flower thrips Frankliniella occidentalis(Thysanoptera:Thripidae)

The western flower thrips, Frankliniella occidentalis, is one of the most destructive sucking pests of vegetables, fruits and ornamental crops in China. Spinosad is one of the most commonly used insecticides to manage thrips. To assess the incidence of spinosad resistance in F. occidentalis field populations in eastern China, survival rates for 24 different populations were compared with those of a susceptible laboratory strain. All populations showed significantly higher resistance to spinosad compared with the control as determined by comparing median lethal concentrations. Two populations from Shouguang and Liaocheng in Shandong Province were classified as having moderate and high levels of resistance to spinosad with a mean resistance ratio of 17.0 and 89.2, respectively. Our research indicates a widespread reduction in spinosad efficacy for controlling F. occidentalis field populations, and that resistance management strategies should be implemented as soon as practicable, to reduce the potential of progressive resistance development and loss of efficacy.

Potential of Steinernema carpocapsae(Weiser) as a biological control agent against potato tuber moth, Phthorimaea operculella(Zeller)(Lepidoptera: Gelechiidae)

The entomopathogenic nematode,Steinernema carpocapsae,was evaluated for control of the potato tuber moth,Phthorimaea operculella,under laboratory conditions.We evaluated different concentrations of S.carpocapsae for control of 2 nd,3 rd,and 4 th instar P.operculella.The median lethal concentration(LC50)of S.carpocapsae infective juveniles(IJs)to 2 nd,3 rd and 4 th instar larvae of P.operculella was 200,363,181 IJs mL–1,respectively.With the extension of treatment time,the cumulative mortality increased for 2 nd,3 rd,and 4 th instar larvae and pupae of P.operculella.Fourth instars were the most susceptible for all observation periods.Therefore,our results suggest that S.carpocapsae could be an effective biological control agent for P.operculella.

Optimization of the sex pheromone-based method for trapping field populations of Phthorimaea operculella(Zeller)in South China

Despite the identification of the potato tuber moth Phthorimaea operculella(Zeller)sex pheromone,no effective application based on this pheromone has yet been developed and evaluated.This study investigated the effect of pheromone lures,trap densities,heights of trap deployment,and pheromone doses in Yunnan,China,for the purpose of increasing the control efficiency of P.operculella and improving the application of pheromone technology in the field.The results showed that lures made of corn oil and red PVC pipes attracted the highest number of moths(11.73±1.90 per trap per day).Sex pheromone loading of 100μg was optimal for trapping moths,but higher doses of pheromone inhibited attraction.The density of traps did not affect capture rates;therefore,the optimum trap density was 30–40 traps ha^(–1).The optimum height of trap deployment was not above the height of the plant canopy.This study provides technical details necessary for the monitoring and control of potato tuber moth using sex pheromones.

The new kid on the block in insect pest management:sprayable RNAi goes commercial

Insect pest damage to crops is a threat to global food security(Tilman et al.,2011).Climate change,the evolution of insecticide resistance,and the phasing out of insecticides due to environmental and safety concerns exacerbate this problem.Farmers urgently need safe and effective crop protection tools to sustainably generate yields that meet ever-increasing global demand.

Establishment of Beauveria bassiana as a fungal endophyte in potato plants and its virulence against potato tuber moth, Phthorimaea operculella (Lepidoptera: Gelechiidae)

The potato tuber moth,Phthorimaea operculella,is the most damaging potato pest in the world and is difficult to control as the larvae are internal feeders in the foliage and tubers.Entomopathogenic fungi that colonize plants as endophytes have lethal and sublethal pathological effects on insect pests.We show that Beauveria bassiana colonizes the aerial parts of potato plants endophytically after inoculation through soil drenching.Endophytic B.bassiana persisted in potato foliage for more than 50 days postinoculation.Bioassays indicated that foliage of B.bassiana-inoculated potato plants were pathogenic against larvae of P operculella.Sublethal experiments indicated that B.bassiana negatively affected the growth,development,and reproduction of P operculella.Development experiments showed that the weight of P.operculella pupae reared on B.bassianacolonized potato plants(4.25 mg)was significantly less than that of those reared on uninoculated control plants(8.89mg).Compared with newly eclosed larvaefed on control plants,those fed on B.bassiana-inoculated plants had significantly lower survivorship,with only 17.8%developing to the adult stage.Oviposition of P operculella females reared on B.bassiana endophytically colonized plants was significantly lower(35 eggs/female)than of those reared on uninoculated plants(115 eggs/female).This study demonstrates that endophytic B.bassiana can be a potential biological control agent for the control and management of P operculella.Comparing pupal weights of P operculella reared on potato plants inoculated with the B.bassiana strain GZGY-1-3 and on untreated control plants,pupae from the control plants were significantly heavier than those from treated plants.