几种杀虫剂防治白菜田棘跳虫的试验

棘跳虫对白菜的为害日益严重,常造成坐蔸、霉烂,对产量和品质及商品价值影响很大。本试验选择几种高效、低毒、对环境安全的杀虫剂4.5%高效氯氰菊酯EC、2.5%溴氰菊酯EC、2%鱼藤粉碎浸液、2%烟碱液和常用农药40%乐果EC、80%敌敌畏EC防治棘跳虫进行大田药效试验,结果表明所有供试药剂对白菜棘跳虫均有较好的防治效果。     

Detoxification of isothiocyanate allelochemicals by glutathione transferase in three lepidopterous species

Glutathione transferase activity towards various plant isothiocyanates was studied in larvae of the two generalists, fall armyworm [Spodoptera frugiperda (J.E. Smith)], and cabbage looper [Trichoplusia ni (Hübner)], and the specialist, velvetbean caterpillar (Anticarsia gemmatalis Hübner) using the midgut soluble fraction as enzyme source. The generalists, but not the specialist, are adapted to feeding on isothiocyanate-containing crucifers. Allyl and benzyl isothiocyanate were found to be metabolized by glutathione transferase from the two generalist species, but no activity was detected with the specialist. The transferase activity towards these allelochemicals in the cabbage looper was two- to sixfold higher than that in the fall armyworm. In all instances, activity was induced by various allelochemicals including indole 3-acetonitrile, indole 3-carbinol, flavone, xanthotoxin, and its own substrates. The induction ranged from 1.3- to 10.1-fold depending on the allelochemical, with the fall armyworm being more inducible. The transferase system of fall armyworm also metabolized another analog, 2-phenylethyl isothiocyanate, but activity can only be observed after induction. Bioassay results showed that these isothiocyanates were all toxic to the lepidopterans, causing acute toxicity in neonates and final-instar larvae. The results suggest that glutathione transferase plays an important role in the detoxification of isothiocyanates and hence food-plant adaptation in phytophagous insects.     

Studies on Hot Air and Microwave Vacuum Drying of Wild Cabbage

Wild cabbage was dehydrated by a combination of hot-air drying and microwave vacuum drying. It showed that the total drying time was reduced by about half while the retention values of the nutrient components and chlorophyll were improved significantly. Microwave/vacuum-dried products had a more porous texture. Finally, microwave drying showed effective bactericidal action in the product with acceptable quality of dried product.     

Identification of male cabbage looper sex pheromone attractive to females

A multicomponent pheromone produced by male cabbage looper moths that is attractive to female moths in a flight tunnel bioassay was isolated and identified. Based on analyses of hairpencil extracts of male cabbage loopers and volatiles emitted by males, the pheromone has been identified as a blend consisting of (S)-(+)-linalool,p-cresol, andm-cresol. The chirality of the major component, (S)-(+)-linalool, is important for behavioral response of females. These pheromonal compounds were also identified as volatiles released by males when males were exposed to the principal pheromone component of female cabbage loopers, (Z)-7-dodecen-1-ol acetate. The amount of male pheromone released was increased significantly when males were exposed to a combination of (Z)-7-dodecen-1-ol acetate and the odor from cabbage. Neither linalool nor the cresols were detected in volatiles from cabbage or from males exposed to cabbage odor.     

Influence of cabbage proteinase inhibitorsin situ on the growth of larvalTrichoplusia ni andPieris rapae

Trypsin and chymotrypsin inhibitors are proteins that are developmentally regulated in foliage of cabbage plants, appearing at high concentrations in young foliage on mature plants. This temporal and spacial regulation of foliar proteinase inhibitors is synchronized with the appearance and distribution of foliar feeding Lepidoptera. When insects were allowed to select their feeding sites, larvalPieris rapae fed on the young foliage of cabbage plants, while larvalTrichoplusia ni fed on the mature foliage on cabbage plants. LarvalP. rapae that fed on mature plants were significantly smaller than larvae feeding on young plants, while there was no significant difference between larvalT. ni feeding on mature plants and those feeding on young plants. Thus, there was a significant inverse correlation between the level of proteinase inhibitory activity in cabbage foliage and larval growth. WhenP. rapae andT. ni were provided with an artificial diet containing total protein (including significant levels of proteinase inhibitors) that was extracted from cabbage foliage, there was a significant reduction in growth and development of both species of Lepidoptera.     

2%春雷霉素WP防治白菜软腐病药效试验

试验结果表明,2%春雷霉素WP对白菜软腐病具有良好的防治效果。室内离体活性EC50值为27.13mg/L,在50、40、30mg/L处理剂量下,对白菜软腐病的平均防效为84.33%、79.31%、67.90%,对作物安全。     

Plant secondary compounds as oviposition deterrents for cabbage butterfly,Pieris rapae (Lepidoptera: Pieridae)

Oviposition byPieris rapae butterflies was deterred by spraying the plant secondary compounds coumarin and rutin on cabbage plants in greenhouse choice tests. In no-choice tests ranging from 5 min to 24 hr, acceptance of rutin-treated plants for oviposition increased with trial duration. Both coumarin and rutin deterred oviposition primarily by affecting prealighting rather than postalighting behavior, indicating that deterrence was mediated by noncontact cues.     

Olfactory responses of the parasitoidDiaeretiella rapae (Hymenoptera: Aphidiidae) to odor of plants,aphids, and plant-aphid complexes

Diaeretiella rapae (M'Intosh) (Hymenoptera: Aphidiidae) is a parasitoid of several aphid species, including the Russian wheat aphid (RWA),Diuraphis noxia (Mordvilko), and the cabbage aphid (CA).Brevicoryne brassicae (L.). The response of matedD. rapae females to odors from wheat, cabbage, and plant-host complexes was investigated using a four-choice olfactometer. Experienced parasitoids, but not inexperienced females, responded positively to odors of the wheat-RWA complex in a no-choice test. In choice tests, experienced parasitoids did not respond to odors of uninfested cabbage and wheat leaves, but did respond positively to aphid-infested plants and to aphids alone. The response ofD. rapae to the cabbage-CA complex and to CA alone was significantly greater than to the wheat-RWA complex and RWA alone, suggesting an innate odor preference for crucifer-feeding aphids.     

Response of <Emphasis Type="Italic">Plutella xylostella</Emphasis> and its Parasitoid <Emphasis Type="Italic">Cotesia plutellae</Emphasis> to Volatile Compounds

The effects of limonene, a mixture of limonene + carvone (1:1, v/v), and methyl jasmonate (MeJA) on diamondback moth (DBM) (Plutella xylostella L.) oviposition, larval feeding, and the behavior of its larval parasitoid Cotesia plutellae (Kurdjumov) with cabbage (Brassica oleracea L. ssp. capitata, cvs. Rinda and Lennox) and broccoli (B. oleracea subsp. Italica cv Lucky) were tested. Limonene showed no deterrent effect on DBM when plants were sprayed with or exposed to limonene, although there was a cultivar difference. A mixture of limonene and carvone released from vermiculite showed a significant repellent effect, reducing the number of eggs laid on the cabbages. MeJA treatment reduced the relative growth rate (RGR) of larvae on cv Lennox leaves. In Y-tube olfactometer tests, C. plutellae preferred the odors of limonene and MeJA to filtered air. In cv Lennox, the parasitoid preferred DBM-damaged plants with limonene to such plants without limonene. C. plutellae females were repelled by the mixture of limonene + carvone. In both cultivars, exogenous MeJA induced the emission of the sesquiterpene (E,E)-α-farnesene, the homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), and green leaf volatile (Z)-3-hexenyl acetate + octanal. The attractive effect of limonene and MeJA predicts that these two compounds can be used in sustainable plant protection strategies in organic farming.     

紫甘蓝色素紫外一可见光谱及日常应用

研究了不同pH值下的紫甘蓝色素吸收光谱，比较它们之间的差异，得出随pH值增大，最大光吸收波长（λmax）向长波方向移动。紫甘蓝色素存在4种互变异构体，且在不同pH值下呈现不同颜色。紫甘蓝色素是一种优良的酸碱指示剂，可以应用于日常生活当中。