First report of cereal cyst nematode(Heterodera filipjevi) on winter wheat in Shandong Province, China

The cereal cyst nematodes(Heterodera avenae,Heterodera filipjevi,Heterodera latipons)are considered to be one of the most important plant parasitic nematodes attacking most cereals and can cause significant crop losses(Sikora 1988).In China,H.filipjevi(Madzhidov 1981)Stelter,1984,was first reported from Henan province(peng et al.2010)and a few years later in Anhui province and Xinjiang Uygur Autonomous Region(peng et al.2016,2018).In December 2017,a survey for cereal

Effect of heat shock on the susceptibility of Frankliniella occidentalis(Thysanoptera：Thripidae) to insecticides

Currently, insecticides are considered as the primary approach for controlling western flower thrips, Frankliniella occidentalis（Pergande）（Thysanoptera： Thripidae）. However, the heavy use of insecticides resulted in high insect resistance and serious environmental pollution. Given its characteristics of ease of operation and environmental friendliness, insect control using high temperature is receiving considerable renewed research interest. However, although the combination of insecticides and high temperature to control F. occidentalis has been studied before, few studies have focused on the short-term effect of such treatment. In a laboratory study, F. occidentalis adults and second-instar nymphs were exposed to 45℃ for 2 h. Then, their susceptibility to acetamiprid, spinosad, methomyl, and beta-cypermethrin was tested after different periods of recovery time（2–36 h）. Additionally, the specific activity of three detoxification enzymes（esterase, glutathione S-transferase, and cytochrome p450（CYP） monooxygenase） of the treated insects was determined. The results indicated that the fluctuation of susceptibility to insecticides and detoxification enzyme activity during F. occidentalis recovery from heat shock are related. Furthermore, several recovery time points（2, 30, and 36 h） of significant susceptibility to four tested insecticides compared with the control were found during the treatment of adults that were heat-shocked. Recovery time points of higher susceptibility compared with the control depended on different insecticides during the second-instar nymph recovery from heat shock. Interestingly, the fluctuation of CYP monooxygenase activity exhibited a trend that was similar to the fluctuation of susceptibility to insecticides（especially spinosad） during the recovery from heat shock of adults. In addition, the glutathione S-transferase and CYP monooxygenase activity trend was similar to the trend of susceptibility to spinosad during the recovery from heat shock of second-instar nymphs. Our results provide a new approach for controlling F. occidentalis using the combined heat shock and insecticide. This effectively enhances the control efficiency of heat shock and significantly reduces the application of insecticides.

PnSCR82,a small cysteine-rich secretory protein of Phytophthora nicotianae,can enhance defense responses in plants

A number of plant pathogenic species of Phytophthora are known to produce different classes of secretory proteins during interactions with their hosts.Although several small cysteine-rich(SCR)secretory proteins,conserved in oomycete pathogens,have been identified in Phytophthora,their specific involvement in these interactions remains unknown.In this study,an SCR effector encoded by Pn SCR82 in P.nicotianae was identified and shown to have similarities to P.cactorum phytotoxic protein,Pc F(Phytophthora cactorum Fragaria).Agroinfection with potato virus X vector,Pn SCR82,was capable of inducing plant hypersensitive cell death in Nicotiana benthamiana and Solanum lycopersicum.Real-time PCR results indicated that transiently expressed Pn SCR82 in N.benthamiana leaves activated the jasmonate,salicylic acid and ethylene signaling pathways.Transient expression of Pn SCR82 enhanced plant resisitance to P.capsici.In summary,our results demonstrated that P.nicotianae Pn SCR82 elicits defensive responses in N.benthamiana and may potentially play a significant role in future crop protection programs.

Landscape genetic analyses reveal host association of mitochondrial haplotypes in the Asian corn borer,Ostrinia furnacalis

Crop expansion often leads to high pest pressure.These pests may have fitness trade-offs related to host use,and some host-associated genotypes may benefit and increase in frequency.However,evidence concerning the effect of host availability on spatial distribution and frequency of mitochondrial haplotypes is scarce.We studied genetic variation of the Asian corn borer,Ostrinia furnacalis(Guenée),across a large area during 2 years(2016 and 2017).Mitochondrial sequence data were obtained from 530 individuals collected from 79 locations in Shandong Province,China.In total,155 haplotypes were found based on the combined cytochrome oxidase subunit 1(COI)and COII genes.Three haplotypes(H2,H12,and H23)were dominant,whereas most of the other haplotypes occurred in low frequency.A haplotype network showed that the 155 haplotypes can be grouped into three clusters.Haplotype clusters seemed to be randomly distributed.The frequency of H12(in Cluster 1)was positively correlated with maize crop proportion,but negatively correlated with other crops(primarily vegetables,oilseed crops,and cotton)at all spatial scales(1-,3-,and 5-km radius).Cluster 2 had haplotype H23,and this cluster was negatively correlated with semi-natural habitats.Cluster 3 had no dominant haplotype and was not affected by landscape factors.We conclude that H12 may be a maize-associated haplotype.Further study is needed to verify the possibility that the carriers of this haplotype may possess some fitness trade-offs.Our study highlights the importance of host availability in O.furnacalis haplotype distribution and frequency.