The Occurrence Of The Insect Pests In Cabbage Fields In Baoding And The Toxicity Determination Of Several New-style Insecticides

Brassica oleracea L. named cabbage is one of cruciferous vegetables. It is widely cultivated throughout the country because of its short cultivation period, high yield, rich in nutrients. There are more than70species of cabbages cultivated mainly outdoor, membrane and greenhouses in Hebei province, such as Gan series, Wanfeng, JingFeng, Qinfeng, etc. Baoding is a vegetable market, but it is difficulty to control and prevent because of its expanding acreage, pest species, occurrence regularity complex. We tested the toxicity of several insecticides on egg and larva of Bemisia (abaci through leaf immersion method, and the moths larva of Plutella xylostella (L.), Spodoptera exigua Hubner, Prodenia litura Fabricius through insect immersion method. The results were as follows.l.Thera were variety pests and natural enemies on cabbage plants with no control during their growth. We studied that there were13species of insect pests, accounted for48.15%, and14species of natural enemies, accounted for51.85%. Even through the species of natural enemies were more than insect pests, it was hard to control insect pests efficiently just rely on natural enemies based on the investigate of cabbage victimization. At present Plutella xylostella, Pieris rapae, aphids were the heaviest insect pest damage to the commodity of cabbage in Baoding area, and the number of Plutella xylostella and aphids was big and harm period was long.2.Through the field investigation in cabbage fields with no chemical control, we studied the spatial distribution pattern of the larvae of Plutella xylostella L. and drew the conclusion that the spatial distribution pattern of the larvae of Plutella xylostella L. was aggregated and density-dependent, the basic ingredients were individual groups, and the gather strength increases with the increase of population density.3.We selected appropriate sex lures in Baoding area provided by three different manufacturers. The best appropriate sex lures of Plutella xylostella L. for Baoding area were the bell lure core rubber provided by Pherobio Technology Co.Ltd. And theirs PVC lures of Spodoptera exigua Hiibner were also the best appropriate sex lures for Baoding area. But the best appropriate sex lures of Prodenia litura Fabricius were the bell lure core rubber provided by Animal of the Chinese academy of sciences. 4. We monitored the occurrence of Plutella xylostella (L.), Spodoptera exigua Hubner, Prodenia litura Fabricius by sex lures. The harm peak of Plutella xylostella (L.) was in late May and June, and in early June and September, the adult mouths were first appeared in early May in Baoding. The harm peak of Spodoptera exigua Hubner was in early and late September, the adult mouths were first appeared in early August. The adult mouths of Prodenia litura Fabricius were first appeared in early mid-August, they often mixed occurred with Spodoptera exigua Hubner and they had four harm peaks, in the middle of August and early September, in late September and early October.5.The toxicities of several new-style insecticides were studied to screen high efficient insecticides against Bemisia tabaci (Gennadius), Plutella xylostella (L.), Spodoptera exigua Hubner and Prodenia litura Fabricius through comparing the LC50value. We concluded that buprofezin25%WP had the highest toxicity to eggs and larva of Bemisia tabaci (Gennadius). The emamectin benzoate1%ME had the highest toxicity to both Plutella xylostella (L.) and Prodenia litura Fabricius,and chlorine benzamide5%SC had the highest toxicity to Spodoptera exigua Hubner. The azadirachtin0.5%EC had the higher toxicity to three insects. But abamectin5%EC and fluorine organism urea5%EC had low toxicity to three insects.