东亚小花蝽对四种害虫的捕食作用

室内饲养的东亚小花蝽Orius sauteri成虫对棉蓟马成虫、烟粉虱4龄若虫、朱砂叶螨雌成螨和甘蓝蚜成虫的捕食作用、种内干扰作用测定结果表明：捕食功能反应均符合HollingⅡ型;东亚小花蝽对棉蓟马的捕食量符合Na=1.0819Nt/（1＋0.08485Nt）,对朱砂叶螨的捕食量符合Na=2.704Nt/（1＋0.1423Nt）,对烟粉虱的捕食量符合Na=1.9641Nt/（1＋0.2455Nt）,对甘蓝蚜的捕食量符合Na=1.5912Nt/（1＋0.1808Nt）。东亚小花蝽的捕食作用有较强的种内干扰反应,捕食率与个体间相互干扰的关系符合Hassell模型。东亚小花蝽的捕食量与害虫密度正相关,寻找效应与害虫密度负相关。在这4种害虫中,小花蝽对朱砂叶螨的瞬间攻击率和最大捕食量均最大、处置时间最短,对棉蓟马的瞬间攻击率最小,对烟粉虱的最大捕食量最小、处置时间最长。     

Heritability of thrips resistance in the ‘IPA-3’ onion cultivar in South Texas

A two season study was conducted to compare the onion cultivars TG1015Y and IPA-3 for resistance to thrips in South Texas. Narrow and broad sense heritabilities were estimated from populations developed from the cross, ‘IPA-3’ × ‘TG1015Y’. Parents, F1, F2, and the respective backcross populations were evaluated for thrips numbers at the Texas Agricultural Experiment Station, Weslaco, TX. ‘IPA-3’ had significantly fewer thrips than ‘TG1015Y’ in both seasons. Yield was significantly different only in the 1996–97 season. The heritability of thrips resistance in this study was very low. Depending on the methods of estimation h ² was 5.3% and 4.0%, and H ² was 4.1% and 8.0%. These results suggest that greater genetic gains for thrips resistance in onion can be achieved by selection on a family basis rather than using single plant selection. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ultralow oxygen treatment for postharvest control of western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae), on iceberg lettuce: II. Effects of pre-treatment storage on lettuce quality

Iceberg lettuce stored under normal atmosphere and controlled atmosphere (CA) with about 3% oxygen at low temperature for 1 week was compared with fresh lettuce for their response to 2 d ultralow oxygen (ULO) treatment with 0.003% oxygen at 10 °C for control of western flower thrips. Lettuce which had been stored for 1 week under normal or CA tolerated ULO treatment while over 30% of fresh lettuce sustained minor injury to heartleaves. Therefore, pre-treatment storage at low temperature enhanced tolerance of lettuce to the subsequent insecticidal ULO treatment. A sequential combination of CA storage and ULO treatment was demonstrated to be effective against western flower thrips and lettuce aphid and safe to all seven lettuce cultivars tested. The study indicated that ULO treatment can be made safer to lettuce through pre-treatment storage to increase lettuce tolerance.     

秦岭山区蓟马种类识别

经1986～1990年5年的采集调查,鉴定出缨翅目昆虫3科、9属、19种,其中中国新纪录种1种。本文着重记述了种类的识别及其寄主与分布。     

6种杀虫剂对葱蓟马的田间药效试验

试验选用1%甲维盐EC、0.3%苦参碱EC、3%阿维·高氯EC、4.5%高效氯氰菊酯EC、2.5%溴氰菊酯EC、42%阿维菌素·毒死蜱EC6种药剂对葱蓟马进行田间药效试验,结果表明供试药剂均具有一定的防治效果.其中4.5%高效氯氰菊酯EC防治效果最好,其次是2.5%溴氰菊酯EC,1%甲维盐EC,6种药剂中42%阿维菌素·毒死蜱EC 防治效果为最差.     

Reduced incidence of tomato yellow leaf curl virus and leafminer in a tomato cultivar in northern Thailand

Tomato yellow leaf curl virus (TYLCV), a whitefly-vectored begomovirus, is a major limiting factor for tomato production worldwide, including Thailand. Field evaluation of commercial tomato cvs. for resistance to the virus endemic in northern Thailand has not been reported. Experiments conducted in northern Thailand in 2011–2013 compared the field performance of three tomato cvs. from the US with a commonly grown Thai cultivar. There were few significant differences observed among the cvs. in marketable yield, and the severity of root-knot and root rot. However there were significant differences noted in TYLCV incidence; virus incidence ranged from 38 to 100% and 8–41% in experiments one and two, respectively. In both experiments ‘Husky Cherry Red’ from the US had the lowest TYLCV incidence, leafminer damage (Liriomyza sp.), and progression of foliar necrosis primarily caused by thrips feeding and possibly exacerbated by air pollution. TYLCV infection was confirmed by a simplified method of nuclear inclusion visualization with light microscopy in experiment one, and by virus inclusion detection and PCR in experiment two.     

The relationship between water‐soluble P and modified Morgan P: results based on data and chemical modelling.

An improved understanding of potential soluble phosphorus (P) loss in run‐off and leachate from agriculturally managed soils presents practical and theoretical challenges. Our study aimed to discover whether modified Morgan extractable P (MMP) can be used to predict water‐soluble P (WSP). We first addressed the relationship between MMP and WSP, and whether MMP is useful for predicting the WSP concentrations demanded by water quality regulations. Secondly, we applied novel soil chemical models to explain why the relationship between MMP and WSP depends upon soil properties. Thirdly, we explain how soil properties relate to potential soluble P loss in situations in which soil is subjected to a wide liquid‐to‐soil ratio (e.g. run‐off and rivers) compared with those with a narrow ratio (e.g. soil porewater). To address these P loss scenarios, 60 agricultural topsoils (0–10 cm) were collected from a mixed‐farming catchment (Lunan catchment, northeast Scotland) and chemically characterized. Theoretical understanding of P solubility was obtained with a P sorption model. The data showed variability in the relationship between MMP and WSP. Modelling shows the MMP versus WSP relationship is nonlinear, depending on several confounding factors (P sorption capacity (PSC), Ca, pH) and the liquid‐to‐soil ratio (L:S) employed for WSP determination. Consequently, the slope of the relationship is not unique but depends subjectively on the set of soils surveyed. MMP versus WSP at large L:S (e.g. in run‐off or rivers) is positively correlated to PSC, whereas at narrow L:S (e.g. porewater) there is a negative correlation with PSC. The study provides new ideas for the interpretation and extrapolation of agronomic soil test data for soils of varied properties and highlights the need to utilize insights from soil chemistry.     

8种杀虫剂对烟蓟马的室内毒力测定

在室内使用浸叶法测定了8种杀虫剂对烟蓟马成虫的毒力。根据不同的杀虫剂对烟蓟马处理不同时间后的结果使用LC50的值进行比较,其毒力效果强弱依次为:多杀霉素>阿维菌素>甲氨基阿维菌素苯甲酸盐>高效氯氰菊酯>噻虫嗪>毒死蜱>辛硫磷>硫丹。此外,生物源杀虫剂的效果更好。     

Maize planting time and arthropod abundance in southern Mindanao,Philippines. II. Population dynamics of natural enemies

Abstract

Beneficial arthropods were monitored in monthly plantings over 4 years in a rainfed, triple-maize cropping system in southern Mindanao, Philippines. Generalist predators and two egg parasitoids of the Asian corn borer Ostrinia furnacalis (Guenée) (ACB) did not show significant differences in abundance with respect to calendar month of planting over 39 crops. Two species of Trichogramma (T. evanescens Westwood and T. chilonis Ishii) collectively parasitized 67% of ACB egg masses and 58% eggs over the study becoming more abundant as the crop aged. The closeness of the two parasitism rates suggests that to increase parasitoid efficacy, particularly early in the crop, the best strategy would be augmentation and to increase longevity of wasps by providing carbohydrate sources to extend their searching time. Unparasitized egg masses tended to be smaller showing they were more likely to be overlooked. The ratio between the two parasitoids was 56:44 in favour of the former. Trichogramma evanescens had been introduced 2 years earlier by a government project, whereas T. chilonis probably was introduced by sugarcane estates. Prior to their introduction there were no ACB egg parasitoids in the Philippines and both are firmly established as annual parasitism levels did not continue to rise during the study. Parasitoid activity caused significant reductions in neonate ACB larval numbers beginning 7 weeks after crop emergence in an average crop. Egg parasitism rates were positively and linearly correlated with ACB egg mass density. A quadratic regression model was established between mean egg parasitism rates and egg masses size with peak parasitism rates occurring at 25 eggs per mass. Collectively 32 species of generalist predators averaged 0.9 – 1.5 individuals per plant based on weekly samplings. If ants were excluded, the average dropped to 0.1 – 0.3 per plant. Ants, dominated by Solenopsis geminata (F.), fed on ACB eggs and larvae. Coccinellids as the next most numerous were represented by three species where Micraspis crocea (Mulsant) in particular tracked ACB egg masses and probably the corn leaf aphid Rhopalosiphum maidis (Fitch) as well. Four species of orthropterans also tracked ACB egg masses. The third most abundant guild was 17 spiders with the oxyopid Oxyopes javanus Thorell and the araneid Araneus inustus (C.L. Koch) highly correlated with ACB egg mass densities. Other spiders targeted ACB moths and Atherigona oryzae Malloch adults. The predatory mirid Cyrtorhinus lividipennis Reuter probably targeted the corn leafhopper Cicadulina bimaculata (Evans) and possibly thrips Thrips palmi Karny and Megalurothrips usitatus (Bagnall). The lacewing Chrysopa sp. was abundant late in the crop when aphids were present on tassels.