Investigation On Insect Pests Of Bambusa Pervariabilis×Dendrocalamopsis Daii In Chishui And Study On Biology And Ecology Of Its Major Pests

Up to date, more than five hundreds species of bamboo have been reported from China, and more than seven hundreds of pests have been reported from bamboo. Bambusa pervariabilisxDendrocalamopsis daii (BP×DD) is a half-bred bamboo by Guangxi Forestry Department at the end of last century, which was diagnosed as a high-yield species by experts from Sichuan Forestry College in Jan. 1992. Its breed and forestation has been regarded as one of National Star Items in 1998. It is pocketbook of mountain fanner and about 200 thousands ha. has been growth in Chishui city. With the development of single-species forestation, pest of BP×DD is becoming a major problem in Chishui city.The kinds of pest of BP×DD, the biology, ecology and management of the major pests are first study and reported, and the results as follows:1. Investigation on insect pests. Forty three species classified in eleven orders, thirty families, of which Orithoptera, Lepidoptera and Homoptera are in the majority, and Algedonia coclesalis Walker and Pterolophia cervina Gressitt are seriously damnous.2. Study on biology of Pterolophia cervina Gressitt. The larva of Pterolophia cervina Gressitt destroies the old bamboo shoot. It finished once life cycle a year, and the old larva lives through the winter and begins at the first ten days of November. In the coming year, pupation in the middle ten days of April, eclosion in the beginning of May, oviposition in the middle ten days of June and incubation in the last ten days of June. The larvae eat into wormhole, and without change of bamboo. If it was changed into anther bamboo, it will die.Mating happened more than once, and without the mating behavior before mated, mating begins when the male and female come together. The adult would like to lay eggs in the new section, furthermore, the diameter of section is the major influence of the place of eggs: the diameter in 2-5 cm are at the first place, and 5-8 cm are the second. There are not any eggs above 8 cm and below 2 cm.3. Study on biology of Algedonia coclesalis Walker. Algedonia coclesalisWalker finishes four or five life cycle a year in Chishui city, and the four times is in the majority. It lives through the winter by the old larva. The mating begin at four o'clock to six o'clock, then the female lay eggs immediately. The data of oviposition lasts twelve days, the peak at the third day to fifth day. The life-span of adult and the average number of egg depend on the feed condition. They come to the peak, 15 to 18 days and 600 eggs at the condition of the intermixture of water and honey (9 to 1).There are seven instars. And the first to the fourth live together, the last instars live alone. The chrysalis live in the soil 1 to 4 cm from the earth's surface. Pupation begins in 2 to 3 days.4. Study on ecology of Algedonia coclesalis Walker. The developmental threshold temperature for the egg, first to seventh instar larva, pupa and adult are: 6.63,12.51,11.18,10.93,10.05,8.01,6.8,5.78,6.2,7.81,8.33℃respectively. And the effective accumulated temperature sums for them are: 124.19,64.54,72.59,82.08,93.46,136.84,155.42,201.06,211.55,111.49,1235.5 degree-day respectively.The death rate of the first instar larva, and the third instar larva of Algedonia coclesalis Walker are high in every temperature. The ratio of sex is nearly 1:1 (♀:♂= 40: 41).The parameter of Algedonia coclesalis Walker are as follows: I=35.62;R₀=(?)=28.93; T=(?)=8.12 weeks; r_m=(lnR₀)/T =0.41;λ=e^r_m =1.51;t=ln2/r_m=1.67 weeks.5.Control measures. Considering the ecology condition of Chishui city, the natural enemy should be play an important role in pest control, and the agricultural management, chemical management and the physical management should be used in some condition.