Studies On The Screening Of The Chinese Citrus Fly Food Attractants And Fungicides

The Chinese citrus fly [Bactrocera minax (Enderlein)] is an important pest of citrus fruit trees, and the damages heavily is generally 10% to 20% in severe cases up to 60% to 90%. This insect has one generation a year, the adults lay eggs in the fruit peel of host, larval feeding and growth and development in the fruit, and leaving the fruit into the soil to pupate after mature. At present, the control methods of the adult stage of Chinese citrus fly are using the food attracts to trap and kill or spraying pesticides in citrus orchard. Therefore, the biological characteristics of adult observed in order to determine the best prevention and treatment period, to filter out the higher attractive activity of the food attractants and insecticidal activity of pesticides are the focus of this research. This research was supported by the national public service sectors (agriculture) scientific special expenditure (200903047-4), the following are major findings:1 The research of biological characteristics of the Chinese citrus flyThe results showed the different treatments of adult eclosion unearthed dynamic and the adult trapping dynamics in citrus orchards, the peak period of the adult eclosion unearthed was shifted to an earlier date, and the successive time was decreased with increased temperatures. Although pupae rearing at the screening house and adult trapping all were in outdoor natural conditions, the beginning, apex, and ending date of adult peak period for trapping in the citrus orchards were later than the screening house for 36 days,30 days and 22 days, respectively. Therefore, it is meaningless to guide the control for adult fly if only based on the citrus orchard trapping data due to its obvious time-lag. However, it is recommended that it is important to using pupae rearing method at screening house for forecasting the adult occurrence period of Chinese citrus fly.Besides,the results suggested by comparing the trap number of citrus orchards and their surrounding shaw trap.In eclosion early of the Chinese citrus fly, the number of the surrounding shaw is much higher than the citrus orchards.therefore, In the citrus orchards prevention and control of the process, we should focus on the surrounding shaw in the early period.2 The research of food attractants Determination of EAG responses found that:The EAG responses of male and female adult was increased with acetic acid, hydrolyzed protein concentration to increase faster,and females increased faster with increasing concentration of ethanol.But male and female adult with brown sugar, orange juice, orange essential oil, ethyl acetate, orange peel powder, citric acid, honey concentration increase did not change significantly. Through research the EAG responses of aqueous solution of different concentrations of the main constituent of the protein hydrolyzate, we can found that, in addition to acetic acid, the EAG responses relative value of other substances are in the range of 0.5 to 0.6, have small changes.Using the orthogonal design and EAG responses, we can get one good formula:brown sugar: ethanol:acetic acid:protein hydrolyzate:honey:water=3:5:26:2:6:100.The EAG responses of the eight kinds of field commonly used formula showed that:the effect of two formulas,20% protein hydrolyzate and 5% sweet orange juice+5%protein hydrolyzate +5%liquor, are the best, and significantly higher than commonly used the mixture of sugar-acetic acid-ethanol. Through 2010 and 2011 field trapping tests prove 20% hydrolyzed protein were significantly higher than other formulations.Through contrast to the EAG responses relative value of conventional and improved the mixture of sugar-acetic acid-ethanol and field attracting effect in 2010, we can found:vinegar and white wine were converted into acetic acid and ethanol in the same active ingredient content,, trapping activity increased. And the mixture of sugar-acetic acid-ethanol is best when used to preparation, storage and contamination will reduce its trapping activity.Through the screening results of field trapping test in 2010 and 2011, costs and other factors into account, we recommend the field trapping formula is the improved of the mixture of sugar-acetic acid-ethanol+0.2% ethyl acetate. The proportion of different substances of brown sugar: ethanol:acetic acid:ethyl acetate:water=5:0.6:0.02:0.2:100.3 The research of insecticide screeningThe EAG response results of the commonly used 15 kinds of insecticides in citrus orchards show that, the value of the EAG responses of the Chinese citrus fly are differents. The EAG responses relative value of trichlorfon original drug, fenvalerate EC, thiophene hydrochloride trihydrate SC is larger, while chlorpyrifos EC, lambda-cyhalothrin EC, hexaflumuron EC, spinosad SC caused EAG response value is smaller. Besides, in addition to trichlorfon and methomyl, the EAG responses of female adult of each pesticide were higher than male adult. Contrast to the six kinds of pesticides screening test in 2011 results can be found that the pyrethroid insecticides has the best control effect, the effect of spinosad and avermectin followed. Traditional organophosphate insecticides have less effective to control the Chinese citrus fly. The effect of maggot fruit of the different approaches of the two pesticides found:From different pharmaceutical comparison, the effect of different approach of phoxim better than the fenpropathrin, and phoxim treatment can effectively reduce the pupation rate of larvae buried and poisoned larvae in the internal fruit or soil surface. From the different processing methods, Dipping fruit treatment effect is the best, spraying fruit treatment followed, spraying the soil is poor. Therefore, from the perspective of maggot fruit processing, the proposal to dip treatment using the phoxim to reduce larvae pupate rate and survival rate of larvae and pupae, which reduces the second year of the pest base.Pupa biocontrol bacteria primaries, screening out of five kinds of better control effect of the bacteria, provides a new approach to the prevention and control of the Chinese citrus fly.