Study On The Occurrence Law And Control Technology Of The Major Soil Insect Pests In The Region Of Puyang

The peanut soil pests are mainly grubs and Neomargarodes gossypii in the Puyang area of Henan province. The grub is a kind of traditional soil pest, and Neomargarodes gossypii is a kind of pest which discovered in recent years. Both of these two pests are seriously harmful to peanuts. Generally they may cause the peanut to reduce production 20%-50%, and seriously may create crop failures. the area impaired have about 12000hm2 every year in Puyang area, causes the farmer to reduce the income 4 million yuan, these two kinds of peanut soil pests have become one of the most important factors which affects the quality and production of Puyang peanut and prevents peanut industrial development.This experiment was carried out from 2004 to 2006, at a total of 18 villages in Puyang County, Qingfeng County, Nanle County, which all locate in the district of Puyang. The research has obtained statistics by random sampling investigating on the wide range, the multi-places, the different time. Through peanut output loss determination under different insect mouth density and the control experiment of different medicament and carrying out method, the result was obtained to be as follows:1.There are mainly three kinds of grubs in the region of Puyang:Holotrichia oblita(Fald.), Holotrichia parallela Motschulsky and Anomala corpulenta Motsch. Holotrichia oblta(Fald.) is the dominant species of Puyang peanut grubs because it takes up 52.3% of the total investigated species. In Puyang, Holotrichia oblita(Fald.) makes a generation every two years. Besides its adult ones and second or third instar larva get through winter in every other years. They live at the space which is 20-30 centimeters below the ground during most of the time in November to December and January to February. They move up by 0-10 centimeters in every March with the rise of the temperature. Holotrichia oblta(Fald.) in the clay, the loam land parcel are more than in the sandy soil land parcel; They are more in the continuous cropping land parcel than in the crop rotation land parcel; Holotrichia oblta be more in exempt plows the land parcel of the machinery harvests and the straw stalk also field than in the executes the well-rotted compost organic base fertilizer and the careful and intensive cultivation land parcel; Number of grubs increases in the soil temperature high land parcel.2.There are also some rules in the occurring of Neomargarodes gossypii. Neomargarodes gossypii belongs to paurometamorphosis insect because of its four stages during his life:egg, nymphae, chrysalides, imago. Its first instar larva harms peanut by pluging its lancets into the roots of the plants and sucking the fluids at the space which is 5-15 centimeters below the ground. Neomargarodes gossypii makes one generation every year in Puyang area. Its second instar larva get through the winter at the soil of peanut root which is 10-15 centimeters below the ground. Neomargarodes gossypii occours mainly in the sand soil and there are less appearances in the clay soil. When the climate is dry or there is too much rain, Neomargarodes gossypii has less occurrence and damage lightly. The higher temperature is, the earlier they occur,the lower temperature is, the later they occur. In different temperatures, the period of identical developmental stage reduces along with temperature increment. The beginning temperature of female ones in egg, nymphae, imago and generation growth are respectively 10.58℃,12.56℃,9.62℃and 13.03℃. Their effective accumulated temperature are respectively:157.12,393.70,135.23 and 680.40d·℃The beginning temperature of male ones in egg, nymphae, chrysalides,imago,generation growth are respectively 10.58℃,12.84℃,11.14℃,9.08℃and 11.78℃. Their effective accumulated temperature are respectively 157.12,422.49,74.70,29.14 and 702.92d·℃. The occurrence of Neomargarodes gossypii is seriouser in continuous cropping land parcel, however Its harm to peanut is obviously less in crop rotation land parcel. The effects are obvious if peanuts are cultivated with non-host plants such as corn, wheat and sweet potatoes. This pest appears less if the land is managed with intensive cultivation. And its best suitable weather condition is warm and dryness days in June.3.48% Lorsban (Chlorpyrifos) EC (350ml/667m2) is the most effective to use in the chemical control the grub larvas. In the experiment of selecting medicaments, the means to prevent the grub is like this:Add water to the medicament to the level of 50kg/667hm2 and spray pesticides to the peanut rhizosphere drop with the manual sprayer removed the nozzle. After 20d the result shows that the adjustment insect mouth decrease rate is 91.40%, control efficiencies is 95.66%, the production increase rate of peanut is 45.09%. Next is 40% Bibensheng. After 20d it shows that the adjustment insect mouth decrease rate is 82.51%, control efficiencies is 87.11%, the production increase rate of peanut is 33.72%.4.Control Neomargarodes gossypii larvas, the better effect is in turn 48% Lorsban EC,5% Regent SC and 1.8% Avermectins EC.Add water to the medicament to the level of 50kg/667hm2 and spray pesticides to the peanut rhizosphere drop with the manual sprayer removed the nozzle. The adjustment insect mouth decrease rate is respectively 68.73%,57.35% and 56.32%; Furrow fertilization with 48% Lorsban EC and 5% Regent SC at sowing time and spurt pesticides to root alternately in the peanut seedling stage, the effect will be better. The adjustment insect mouth decrease rate is respectively 74.73% and 71.24%. The suggestion promotes the means that both 48% Lorsban EC and 5% Regent SC are spurted alternately.