The potential of using insecticidal properties of medicinal plants against insect pests

In this study, botanicals extracted from two the species of family Scrophulariaceae, Verbascum cheiranthifolium Boiss and Verbascum speciosum Schard, were examined for their effect on mortality and progeny production against adults of Sitophilus oryzae (L.). The plant extracts were applied at five dose rates, which 0.25, 0.5, 1.0, 2.0 and 3% (w/v). Adults of S. oryzae was exposed to the treated wheat at 25 degrees C and 65% RH and mortality was assessed after 24 h, 48 h, 7 day, 14 day and 21 day of exposure. Then all adults were removed and the treated substrate remained at the same conditions for an additional 45 day after this interval, the commodity was checked for progeny production. In use two extracts the mortality of adults increased with the increase of dose and exposure interval so that; mortality was 100% after 21 days of exposure at the highest dose rate. Results indicated that applied of V. cheiranthifolium extract was more effective than V. speciosum against adult insects. Interestingly, in two cases complete suppression (100% reduction) of the progeny production (F1) was observed in the treated wheat than in control even in the lowest dose rate. Therefore, our results indicate that these medicinal plants can be used for protection of stored grain from infestations of stored-product insect pests.     

黑龙江省无公害大豆生产中的病虫害防治技术

针对黑龙江省无公害大豆生产中的病虫害,提出了包括土壤管理、种子管理、化学防治综合防治技术措施.以期为黑龙江省无公害大豆生产中的病虫害防治提供技术依据.     

Daily application of ultra-low-volume (ULV) insecticides at low dosages to control insect pests of cotton in Malawi

ULV carbaryl and DDT were applied to cotton (Gossypium hirsutum) at two sites, five times a week, using five swath widths from 4·5 to 18 m, representing high to low dosages. Sprays were applied between 0830 and 1400 h during the day or between 1830 and 2100 h during the evening. Subsequently, Bemisia spp. (whitefly) and Paurocephala gossypii Russell (psyllid) populations were significantly larger on plants treated with lower dosages applied over wide swaths. Yields of seed cotton were significantly lower from plants treated with low dosages (< 0·5 kg a.i./ha weekly) but the results of spraying in the morning and in the evening were comparable, at both sites.     

转基因抗除草剂油菜对春油菜区主要害虫发生数量的影响

对转基因抗除草剂油菜品种、受体及当地常规品种在春油菜区主要害虫种群的数量进行了调查。结果表明,不同品种间几种主要害虫的发生数量之间存在极显著或显著差异,进一步分析表明,这种差异主要表现为转基因抗除草剂品种与受体品种之间的差异,而与当地的常规品种之间无显著差异。     

Effects of simulated insect defoliation on potatoes

There were 3 distinct periods during which 100% defoliation affected yield parameters of potatoes. Plants were especially susceptible to defoliation 3–5 weeks after 50% stand emergence. In a weekly defoliation study, the 29% defoliation level had no effect on yield but the weekly 58% level significantly reduced yield. An equation relating fresh plant weight to leaf area was developed.     

Varietal differences in the response of potatoes to repeated short periods of water stress in hot climates. 1. Turgor maintenance and stomatal behaviour

Summary The response of six potato cultivars, Désirée, Up-to-Date, Alpha, Elvira, Spunta and Troubadour, to water stress under high ambient temperatures was investigated. Osmotic regulation in the leaves of all six cultivars was highest in Alpha and the lowest in Troubadour. Concomitantly, Alpha maintained the highest turgor potential under water stress while Troubadour had the lowest values indicating a relationship between the degree of osmotic regulation and maintenance of turgor. The highest stomatal conductance under water stress was exhibited by Désirée while both stressed and non-stressed plants of Up-to-Date had the lowest values. In addition, Up-to-Date had a larger root system than Désirée. The association of these traits with tolerance to short periods of drought in the potato is discussed. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel, No 295-E, 1981 series. The investigation was supported in part by a grant from the Ministry for Development Cooperation of the Netherlands.     

Pheromones for the control of insect pests in Mediterranean countries

Pheromones can be used to monitor insect populations or to control directly certain pest species by mass-trapping or mating-disruption techniques. The potential advantages of using pheromones for crop protection in these various ways are illustrated by examples taken mainly from work conducted in the Mediterranean region by members of the Scientific Units of the Overseas Development Administration.     

Evaluation of some systemic granular insecticides againstMyzus persicae Sulzer on potatoes

Summary Field evaluation of seven granular insecticides againstMyzus persicae revealed that phorate, aldicarb and disulfoton (both Di-Syston and Solvirex) are effective in reducing and keeping down the population ofM. persicae when applied either at sowing or at first earthing up.     

Modelling and simulating commercial hot water blanching of potatoes

A method of applying the leaching model for hot water blanching to predict component losses during commercial scale potato processing was developed. The method involves characterizing an individual blancher to adjust the model to account for nonuniform mixing flow. The leaching model is based on the assumption that the water in the blancher is completely back mixed and the temperature and concentration are uniform throughout. The concentration of the blanch water for back mix flow was calculated using the mean blancher temperature. The blanch water concentration for nonideal flow (e.g., plug flow) corresponding to the temperature distribution was calculated. Using some combination of back mix and plug flow the blanch water concentration was calculated. Comparing the calculated and experimental values, a factor to adjust the model-calculated concentration to agree with the real value was determined. This factor then is used to correct future calculations made on this particular blancher with the model. Potassium is used as a key component because it is stable for sampling and analysis. However, the method should work for other components.     

福州市五爪金龙（Ipomoea cairica）的主要病虫害种类

首次对福州市外来入侵植物五爪金龙（Ipomoea cairica）的病虫害种类进行了较为系统调查,结果发现昆虫有甘薯褐龟甲（Leccoptera quadrimaculata）、甘薯小绿龟甲（Cassida circumdata）2种;病害为炭疽病,鉴定为胶胞炭疽菌（Colletotrichumgloeosporioides）,室内接种表明其致病力较弱。从根部土壤分离到双宫螺旋线虫（Helicotylenchus dihystera）、燕麦滑刃线虫（Aphelenchus avenae）、螺旋线虫（Helicotylenchussp.）、滑刃线虫（Aphelenchoidessp.）、丝尾垫刃线虫（Filenchussp.）等5种病原线虫。冻害在福州地区可发生,但不会造成植株死亡。以上表明五爪金龙的自然天敌种类很少,是造成福州地区五爪金龙为害严重的原因之一。     

Insecticidal effect of two novel pyrrole derivatives against two major stored product insect species

Several pyrrole compounds exhibit insecticidal properties against a wide range of insect pest species. In the present work, the insecticidal effect of the two new pyrrole derivatives, ethyl 3-(benzylthio)-4,6-dioxo-5-phenyl-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrrole-carboxylate (3i) and isopropyl 3-(benzylthio)-4,6-dioxo-5-phenyl-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrrole-carboxylate (3k) were studied as stored-grain protectants (maize and barley) against two major stored-product insect species, the confused flour beetle, Tribolium confusum Jaquelin du Val (Coleoptera: Tenebrionidae) adults and larvae and the Mediterranean flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) larvae at three doses (0.1, 1 and 10 ppm) and five exposure intervals (1, 2, 7, 14 and 21d). All T. confusum adults were dead at all doses on barley treated with 3i after 21d of exposure, while for 3k mortality was >92%. Progeny production was very low (≤1 individual per vial) at all doses for both pyrrole derivatives. Mortality of T. confusum larvae was not complete with any dose of both pyrrole derivatives but it exceeded 96% with 3k at 10 ppm after 21d of exposure on maize. For barley, all exposed larvae were found dead at all doses of both pyrrole derivates after 7d of exposure. Mortality of E. kuehniella larvae was complete at 1 and 10 ppm of 3i and all doses of 3k at 7d of exposure. After 14d of exposure, all E. kuehniella larvae were dead at 0.1 ppm of 3i. The results of the present study indicate that the tested compounds have elevated insecticidal effect against both species tested on certain combinations of dose, exposure interval and type of commodity.