Influence of edible fruit coatings on Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) oviposition and development

Drosophila suzukii (Matsumura) is a highly invasive vinegar fly recently detected in the United States that severely threatens the viability of soft skinned fruit production. Insecticides mitigate some of this damage, but alternative methods to manage D. suzukii infestation are needed. We tested three edible coatings to determine if they could prevent or reduce oviposition by D. suzukii females or affect immature survivorship and development in two important host crops, blueberry and raspberry. None of the coatings prevented oviposition, but some reduced the number of eggs laid. Two carnauba wax-based coatings, PrimaFresh 45 and Raynox, dramatically reduced survivorship of immature D. suzukii in raspberries, but not in blueberries. Our results suggest that obtaining thorough, even coverage in the field will be essential if edible coatings are to be used as a management strategy for D. suzukii.     

变温下铃木氏果蝇年龄-阶段两性生命表研究

为进一步阐明温度对铃木氏果蝇生长发育和繁殖的影响,补充铃木氏果蝇基础生物学信息,本研究在室内14~20℃、26~32℃变温条件下人工饲养铃木氏果蝇,对比不同变温条件下铃木氏果蝇的发育历期、存活率和繁殖率,并构建年龄-阶段两性生命表。结果表明:与26~32℃处理相比,14~20℃变温处理下铃木氏果蝇的各阶段发育历期、成虫寿命及产卵前期均较长。14~20℃变温处理下该虫年龄-阶段特征存活率(sxj)、年龄-特征存活率(lx)、年龄-阶段特征生殖能力(vxy)以及期望寿命(exy)均高于26~32℃处理,而繁殖力(fxj、mx)低于26~32℃处理。14~20℃变温处理下该虫的内禀增长率(rm)和周限增长率(λ)低于26~32℃处理,而平均世代周期(T)和种群加倍时间(t)高于26~32℃处理。在变温条件下,高温相较于低温更利于铃木氏果蝇的种群增长。     

斑翅果蝇卵致死低温研究

为有效防止斑翅果蝇疫情扩散,降低传播风险,本研究以斑翅果蝇(Drosophila suzukii Matsumura)卵为研究对象,对该果蝇在3.0±0.5℃和5.0±0.5℃下低温处理致死时间进行研究。通过卵分别在1℃、3℃、5℃、7℃、9℃、11℃、13℃、15℃、17℃等9个不同温度条件下进行孵化培养,以期摸索出斑翅果蝇相关致死低温。结果表明:在3±0.5℃和5±0.5℃条件下,斑翅果蝇卵的致死时间分别为5.4 d和9.5 d。通过回归模型推算,恒温培养斑翅果蝇卵的致死低温为6℃。     

Field evaluation of commercial plant extracts against Drosophila suzukii (Diptera: Drosophlidae) in raspberry

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) was detected in 2008 in southern Europe and North America and it has spread rapidly throughout the two continents mainly affecting thin-skinned berries and stone fruits which constitute an important, economic and social driver in these regions. This study analyzes the potential control ability of four commercial plant-derived extracts, namely Sophora flavescens (shrubby sophora), Cinnamomum zeylanicum (cinnamon), Capsicum frutescens (chili) and Allium sativum (garlic), against D. suzukii, under raspberry high tunnel field conditions. Extracts were applied in a randomized complete block design using spinosad as positive control. As expected, spinosad treatment resulted in a satisfactory control, reducing significantly the number of larvae and adults emerged from treated fruits even ten days after application. Sophora flavescens extract produced a significant reduction of 60.7% in emerged adults, with no reduction in the number of larvae, six days after application. In addition, garlic extract caused significant reduction in the mean number of larvae (over 50%) and emerged adults (over 48%) six days after application. These findings suggest that garlic and S. flavescens affect egg viability and/or larvae development. Tentative explanations about the variability of the results and possible benefits of repetitive treatments are discussed.     

Report of Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) from the high-altitude and cold arid region of Ladakh,India

Drosophila suzukii (Matsumura, 1931) is here reported for the first time from the high-altitude and cold arid region of Ladakh, which is a Northwestern Himalayan region of India and is the second coldest inhabited place in the world. The species is emerging in the Ladakh region as a serious apricot pest, causing a considerable amount of economic loss.     

Drosophila suzukii (Diptera: Drosophilidae) distribution modelling improves our understanding of pest range limits

Abstract

Spatial distributions models (SDM) are often used in invasive pest management to understand current and potential distribution. Using data on the well-studied spotted wing drosophila as a model, we compared distribution patterns of the range-limit with commonly applied correlative and mechanistic models. Correlative models risk underestimation whereas simple mechanistic models provide overestimated range predictions, although using both approaches for the spotted wing drosophila improved range-limit predictions. Model choice when dealing with pests is central to the accurate identification of invasive species limit range and consequently for the deployment of monitoring and early detection programs.     

Laboratory survival of Drosophila suzukii under simulated winter conditions of the Pacific Northwest and seasonal field trapping in five primary regions of small and stone fruit production in the United States

BACKGROUND: Drosophila suzukii was first found in Oregon in August 2009. The threat of this pest to regional small and stone fruit production industries led to investigations on its overwintering capabilities in fruit‐growing regions in the Pacific Northwest. Knowledge of its cold tolerance will help in the development of computer models to forecast seasonal population growth and decline. RESULTS: Of 1500 adults or pupae, 22 (1.4%) individuals survived the 84 day experimental chilling period. Most (86%) of the survivors were subjected to 10 °C temperature treatments. Survival decreased significantly at lower temperature treatments. Freezing temporarily increased the mortality rate but did not significantly affect overall mortality over the trial period. Flies that emerged from pupae are estimated to survive for up to 103–105 days at 10 °C and for shorter periods at lower temperatures. Field trapping in five fruit production areas has demonstrated overwintering survival in California and Oregon, but lower survival is predicted in Eastern Washington and Michigan. CONCLUSION: The experiments reported here indicate that long‐term survival of D. suzukii is unlikely at temperatures below 10 °C. Field data from five climatic regions indicated extended low initial D. suzukii field presence in 2010 in all regions except California, where field presence was recorded earlier. Copyright © 2011 Society of Chemical Industry