杀虫剂对不同寄主植物上的小菜蛾幼虫羧酸酯酶的体内抑制

敌敌畏对取分西洋菜，菜心和萝卜的小菜蛾４龄幼虫β－ＮＡ羧酸酯酶的体内抑制动态规律有显著的差异。取食不同寄主植物的小菜蛾β－ＮＡ羧酸酯酶活性在受到敌敌畏的的抑制之后，其恢复速度不同，取食西洋菜的小菜蛾幼虫β－ＮＡ羧酸酯酶活性的恢复速度明显高于取食菜心和萝卜的小菜蛾。     

5%氟虫腈胶悬剂防治小菜蛾试验

田间试验结果表明，５％氟虫腈胶悬剂对小菜蛾具有高效、速效和持效期长的特点。在小菜蛾低龄幼虫高峰期，亩用氟虫腈２０～３０毫升，其防效和持效期显著高于定虫隆和氰戊菊酯     

5%定虫隆与4.5%高效氯氰菊酯乳油混剂对小菜蛾的室内毒力测定

采用浸叶法在室内条件下测定5％定虫隆、4．5％高效氯氰菊酯单剂以及不同配比混剂对小菜蛾幼虫的毒力。室内毒力测定结果表明,5％定虫隆与4．5％高效氯氰菊酯4种混剂对小菜蛾均有显著的增效作用,其中混配2的增效作用最显著,其共毒系数最高为367．22。     

寄主和药剂对斜纹夜蛾影响

陈永明，吴坤君（2001）认为，寄主植物与食料植物的含义是不同的，后果是泛指昆虫某一虫态所能取食的一切植物Zalucki等认为，要确认真正的寄主植物必须符合下述两个条件之一，能在活体上将幼虫一直饲养到成虫（或化蛹），     

寄主植物和温度对东方黏虫生长发育的影响

测定了寄主植物和温度对东方黏虫生长发育的影响，结果表明：1）幼虫分别取食寄主植物玉米，高粱、水稻和狗尾草后，虫重增加速度最快的是高粱，其次依次为玉米，狗尾草和水稻；以取食高粱的试虫幼虫历期最短，而蛹重最大；以取食水稻的试虫幼虫历期最长，蛹重最轻，化蛹率最低；2）幼虫在20℃，25℃和30℃三个生长温度下，25℃时的试虫蛹重较大，化蛹率较高。     

定虫隆与高效氯氰菊酯对小菜蛾毒力最佳配比的筛选

采用浸叶法测定了定虫隆与高效氯氰菊酯混配后对防治小菜蛾3龄幼虫的增效作用及两种药剂混配的最佳配比。结果表明,当定虫隆与高效氯氰菊酯的配比在19.20∶35.00～24.00∶0.00之间时,混配药剂表现出增效作用;而当两种药剂的比为20.64∶4.50时,增效作用最强,此时的共毒系数最高为162。     

蔬菜顽敌——小菜蛾防治经验谈

小菜蛾的主要寄主植物为十字花科蔬菜，以甘蓝、花椰菜，大白菜，油菜等受害最重，有时也为害其他温室蔬菜，小菜蛾是蔬菜的主要害虫，小菜蛾一龄幼虫孵出后不久即潜入叶片组织内取食叶肉，二龄后即从叶组织内钻出，多数在叶背为害，取食下表皮和叶肉，仅留下上表皮呈透明小斑点。成熟幼虫可以将叶片咬成空洞和缺缺刻仅留下叶脉，严重时叶片被吃成网状。在甘蓝、大白菜苗期常集中为害心叶，影响包心，还可为害嫩茎和子荚，影响留种菜的留种。凡十字花科蔬菜连作的菜区，小菜蛾常猖獗成灾，故有”世界性难治的顽固害虫”之称。     

4种抗生素类杀虫剂对小菜蛾不同龄期幼虫的毒力和杀卵作用

采用浸渍法测定了梅岭霉素、阿维菌素、浏阳霉素和多杀菌素对小菜蛾2龄、3龄、4龄幼虫的毒力，以及对虫卵的生物活性。结果表明：4种药剂对小菜蛾不同龄期幼虫的毒力均以梅岭霉素最高，阿维菌素和多杀菌素次之，浏阳霉素的毒力最小；4种药剂对不同龄期幼虫的毒力还随虫龄的增加而降低。梅岭霉素对卵的孵化有一定抑制作用；小菜蛾的卵经梅岭霉素、阿维菌素和多杀菌素处理后其初孵幼虫的存活率显著降低。     

14种杀早剂对小菜蛾的药效试验

近年来小菜蛾在我国北方的发生呈明显上升趋势。１４种杀虫剂对山东泰安小菜蛾的室内及田间试验表明：喹硫磷，辛硫磷，Ｂ．ｔ．乳剂，氟虫脲和定虫隆防效均在８０％以上；双甲脒亦有较好防效，田间施药后５－７天，防效为８０．５－８２．３％；４种拟除虫菊酯类杀虫剂及灭多威对该虫效果差。     

14种杀虫剂对小菜蛾的药效试验

近年来小菜蛾在我国北方的发生呈明显上升趋势，１４种杀虫剂对山东泰安小菜蛾的室内及田间试验表明：喹硫磷、辛硫磷、Ｂ．ｔ．乳剂、灭幼脲、氟虫脲和定虫隆防效均在８０％以上；双甲脒亦有较好防效，田间施药后５～７天，防效为８０．５～８２．３％；４种拟除虫菊酯类杀虫剂及灭多威对该虫效果差。     

Identification of BcARR Genes and CTK Effects on Stalk Development of Flowering Chinese Cabbage

Flowering Chinese cabbage (Brassica campestris L. ssp. Chinensis var. utilis Tsen et Lee) is an important and extensively cultivated vegetable in south China, whose major food product is the stalk. In the process of stalk formation, its initiation and development are regulated by a series of hormonal signals, such as cytokinin and gibberellin. In this study, we analyzed the effects of zeatin (ZT) and gibberellin A3 (GA3), and their interaction, on the bolting of flowering Chinese cabbage. The results indicated that the three-true-leaf spraying of ZT and GA synthesis inhibitor (PAC) inhibited plant height but increased stem diameter. Cytokinin (CTK) synthesis inhibitor (YZJ) and GA3 treatment increased plant height and decreased stem diameter. In addition, ZT and GA3 co-treated plants displayed antagonistic effect. Further, 19 type-B authentic response regulators (ARR-Bs), the positive regulators of cytokinin signal transduction were identified from flowering Chinese cabbage. Comprehensive analysis of phylogeny showed BcARR-Bs clustered into three subfamilies with 10 conserved motifs. Analysis of their expression patterns in different tissues and at various growth stage, and their response to hormone treatment suggest that ARR1-b localized in the nucleus displayed unique highest expression patterns in stem tips, are responsive both to ZT and GA, suggesting a significant role in mediating the crosstalk of ZT and GA in the bolting of flowering Chinese cabbage.     

Experience-Induced Habituation and Preference Towards Non-Host Plant Odors in Ovipositing Females of a Moth

In phytophagous insects, experience can increase positive responses towards non-host plant extracts or induce oviposition on non-host plants, but the underlying chemical and behavioral mechanisms are poorly understood. By using the diamondback moth, Plutella xylostella, its host plant Chinese cabbage, and a non-host plant Chrysanthemum morifolium, as a model system, we observed the experience-altered olfactory responses of ovipositing females towards volatiles of the non-host plant, volatiles of pure chemicals (p-cymene and α-terpinene) found in the non-host plant, and volatiles of host plants treated with these chemicals. We assessed the experience-altered oviposition preference towards host plants treated with p-cymene. Naive females showed aversion to the odors of the non-host plant, the pure chemicals, and the pure chemical-treated host plants. In contrast, experienced females either became attracted by these non-host odors or were no longer repelled by these odors. Similarly, naive females laid a significantly lower proportion of eggs on pure chemical-treated host plants than on untreated host plants, but experienced females laid a similar or higher proportion of eggs on pure chemical-treated host plants compared to untreated host plants. Chemical analysis indicated that application of the non-host pure chemicals on Chinese cabbage induced emissions of volatiles by this host plant. We conclude that induced preference for previously repellent compounds is a major mechanism that leads to behavioral changes of this moth towards non-host plants or their extracts.     

Variation In Plant Volatiles and Attraction Of The Parasitoid<Emphasis Type="Italic">Diadegma semiclausum</Emphasis>(Hellén)

Differences in allelochemistry of plants may influence their ability to attract parasitoids.We studied responses of Diadegma semiclausum (Hellén), a parasitoid of the diamondback moth (Plutella xylostella L.), to inter- and intraspecific variation in odor blends of crucifers and a non-crucifer species. Uninfested Brussels sprout (Brassica oleracea L. gemmifera), white mustard (Sinapis alba L.), a feral Brassica oleracea, and malting barley (Hordeum vulgare L.) were compared for their attractivity to D. semiclausum in a Y-tube bioassay. Odors from all plants were more attractive to the parasitoid than clean air. However, tested against each other, parasitoids preferred the volatile blend from the three cruciferous species over that of malting barley.Wasps also discriminated between uninfested crucifers: mustard was as attractive as feral B. oleracea, and both were more attractive than Brussels sprout. Attractivity of uninfested plants was compared with that of plants infested by larvae of the host P. xylostella. Host-infested mustard and Brussels sprout were more attractive than uninfested conspecifics. Interestingly, the volatile blends of uninfested white mustard and infested Brussels sprout were equally attractive.We also compared the volatile composition of different plant sources by collecting headspace samples and analysing them with GC-MS. Similarities of volatile profiles were determined by hierarchic clustering and non-metric scaling based on the Horn-index. Due to the absence of several compounds in its blend, the volatile profile of barley showed dissimilarities from blends of crucifers. The odor profile of white mustard was distinctly different from the two Brassicaceae.Feral Brassica oleracea odor profile was different from infested Brussels sprout, but showed overlap with uninfested Brussels sprout. Odor blends from infested and uninfested Brussels sprout were similar, and mainly quantitative differences were found. D. semiclausum appears to discriminate based on subtle differences in volatile composition of odor blends from infested and uninfested plants.     

Experience Induces a Phytophagous Insect to Lay Eggs on a Nonhost Plant

Experience of nonhost plants by phytophagous insects may alter their foraging and oviposition responses to these plants. Using the diamondback moth (DBM) Plutella xylostella (L.), its host-plant Chinese cabbage, and a nonhost-plant Pisum sativum (pea) as a model system, we examined whether experience of the nonhost plant by adults can induce oviposition on the nonhost plant. Naive DBM females did not accept pea for oviposition in either no-choice or choice conditions, whereas females with prior experience of pea laid up to 20% of their eggs on this plant. Naive females reduced their oviposition, but experienced females did not refrain from laying eggs in a nonhost-plant environment. Such habituation to nonhost plants could lead to host range expansion in phytophagous insects and increase mortality of pest insects in diversified crop systems.     

Identification of DELLA Genes and Key Stage for GA Sensitivity in Bolting and Flowering of Flowering Chinese Cabbage

Flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee) is an important and extensively cultivated vegetable in south China, and its stalk development is mainly regulated by gibberellin (GA). DELLA proteins negatively regulate GA signal transduction and may play an important role in determining bolting and flowering. Nevertheless, no systematic study of the DELLA gene family has been undertaken in flowering Chinese cabbage. In the present study, we found that the two-true-leaf spraying of gibberellin A3 (GA₃) did not promote bolting but did promote flowering, whereas the three-true-leaf spraying of GA₃ promoted both bolting and flowering. In addition, we identified five DELLA genes in flowering Chinese cabbage. All five proteins contained DELLA, VHYNP, VHIID, and SAW conserved domains. Protein-protein interaction results showed that in the presence of GA₃, all five DELLA proteins interacted with BcGID1b (GA-INSENSITIVE DWARF 1b) but not with BcGID1a (GA-INSENSITIVE DWARF 1a) or BcGID1c (GA-INSENSITIVE DWARF 1c). Their expression analysis showed that the DELLA genes exhibited tissue-specific expression, and their reversible expression profiles responded to exogenous GA₃ depending on the treatment stage. We also found that the DELLA genes showed distinct expression patterns in the two varieties of flowering Chinese cabbage. BcRGL1 may play a major role in the early bud differentiation process of different varieties, affecting bolting and flowering. Taken together, these results provide a theoretical basis for further dissecting the DELLA regulatory mechanism in the bolting and flowering of flowering Chinese cabbage.     

黄荆提取物对几种害虫的杀虫活性

研究了黄荆种子二氯甲烷提取物对5种害虫的杀虫活性以及对天敌异色瓢虫的安全性。结果表明：黄荆提取物对菜青虫、小菜蛾、麦长管蚜和桃蚜都有较高的杀虫活性，尤其是对菜青虫的活性最高，稀释100倍，处理4龄幼虫死亡率可达93．3％。但对大猿叶甲的杀虫活性则很低。黄荆提取物对异色瓢虫幼虫有一定的杀虫活性，但对其成虫无任何影响。本研究结果为开发利用这一新的杀虫植物资源提供了依据。     

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.     

新化合物HNPC-A8008对鳞翅目害虫的活性及田间防治效果

[目的]评价新化合物HNPC-A8008[5-(3-氯烯丙基)氨基-1-(2,6-二氯-4-三氟甲基)苯基-4-三氟甲基亚磺酰基吡唑-3-腈)]对几种鳞翅目害虫的室内杀虫活性和田间防治效果。[方法]分别采用浸渍法和常规喷雾法进行室内毒力测定和田间药效试验。[结果]HNPC-A8008对鳞翅目害虫黏虫、菜青虫、小菜蛾、斜纹夜蛾48 h的LC50值分别为0.73、0.94、1.14、25.70 mg/L;在剂量为15、30、45 g a.i./hm2时,药后1、3、7 d对小菜蛾和菜青虫的田间防效分别超过了81.41%、89.80%;在剂量为30、60、90 g a.i./hm2时,药后14 d,对稻纵卷叶螟和二化螟的田间防效分别超过了66.99%、72.32%。[结论]新化合物HNPC-A8008在室内对多种鳞翅目害虫表现出很高的毒杀活性;对小菜蛾、菜青虫、稻纵卷叶螟、二化螟有良好的田间防治效果,且对作物和天敌安全。     

Release of potassium from K-bearing minerals: Effect of plant roots under P deficiency

Pot experiments were conducted, with ryegrass (Lolium perenneL.) maize (Zea mays L ND60) and pak-choi (Brassica campestrisL. ssp.chinensis (L.) Mokina. var. cammunis Tsen et Lee, cv. Wuyueman), to investigate plant mobilization of mineral K in gneiss and feldspar under P-deficient conditions. For both pak-choi and maize grown in gneiss, P-starvation led to a significant increase in K concentration in their shoots, and the net release of K from the mineral K pool was significantly enhanced when the crops grew in feldspar. The enhanced mobilization of mineral K might be attributed to the release of organic acids from the plant roots. When gneiss of various particle sizes was exposed to malic and tartaric acids, both acids had a direct positive influence on the release of mineral K from gneiss. More release of K was observed with increasing concentration of both organic acids, much more so for finer particle size fractions.