Evaluation of Control Effects against Sugarcane Pests：A New Sustained-release and Long-lasting Pesticide and Convenient and Efficient Pesticide Application Technology

[Objective]The paper was to screen a new ideal sustained-release,long-lasting and low-toxic pesticide and convenient and efficient pesticide application technology for controlling Ceratovacuna lanigera and Baliathrips serratus. [Method]2% Imidacloprid GR were selected and applied in the soil for field efficacy trial. [Result] The optimum dosage of 2% imidacloprid GR was 30 kg/hm^2（ active ingredient 600 g）,which can be mixed with fertilizer（ 30 kg pesticide and 40-80 kg fertilizer per hm^2） once combined with sugarcane planting management or big ridging during February and June. The control effects against C. lanigera and B. serratus could be more than 98. 2% and 81. 1%,respectively. The actual yield and sugar content in various pesticide treatments were increased by 33 390 kg/hm^2 and 6. 6% respectively compared to blank control. [Conclusion]2% imidacloprid GR has good control effects on C. lanigera and B. serratus. It is a new pesticide with ideal sustained-release,long-lasting and low-toxin effects against C. lanigera and B. serratus. Therefore,it could be used alternatively with other pesticides,to delay production and development of drug resistance.

Effect of Pesticides on Growth of Rhizobia and Their Host Plants During Symbiosis

Effect of various pesticides (insecticides, fungicides and herbicides) has been studied on growth and efficiency of symbiotic properties of 3 fast growing Rhizobium sp. under green house conditions. The results revealed adverse effects on plant growth and nitrogen fixing capacity as measured by dry weight and total nitrogen content of plants infected with pesticide treated Rhizobium. Of the pesticides tested, herbicides were found to be more effective on the above parameters than the insecticides and fungicides.

Effects of selected insecticides on Diadegma semiclausum（Hymenoptera： Ichneumonidae） and Oomyzus sokolowskii （Hymenoptera： Eulophidae）, parasitoids of Plutella xylostella （Lepidoptera： Plutellidae）

Field doses of six selected insecticides were tested against the immature(pupae) and mature (adult) stages of Diadegma semiclausum (Hellen) and Oomyzus sokolowskii(Kurdjumov), parasitoids of the diamondback moth, Plutella xylostella (L.). Effects of contacttoxicity (direct spraying) of the six insecticides on emergence of parasitoids were found negligibleon both species except permethrin which caused 37.5% mortality. All adults of both parasitoidspecies died 24 hours after exposure to chlorfenapyr, emamectin benzoate and permethrin. Incontrast, the three insect growth regulators (IGRs), chlorfluazuron, flufenoxuron and teflubenzuron,were found harmless to both species, and adult mortality of both parasitoid species was 0—16.7%.However, parasitism by the females of both parasitoid species was severely impaired when the femaleswere offered the three IGR diluted solutions for 24 hours. Effects of oral toxicities of the IGRson longevity of both parasitoids after 12 hours exposure were found to be significantly differentbetween males and females. Compatibility of tested insecticides with D. semiclausum and O.sokolowskii and integration of compatible insecticides with these parasitoids in integrated pestmanagement programs of crucifers are discussed.

Microencapsulated chlorpyrifos: Degradation in soil and influence on soil microbial community structures

Degradation kinetics of microencapsulated chlorpyrifos （CPF-MC） in soil and its influence on soil microbial community structures were investigated by comparing with emulsifiable concentration of chlorpyrifos （CPF-EC） in laboratory. The residual periods of CPF-MC with fortification levels of 5 and 20 mg/kg reached 120 days in soil, both of the degradation curves did not fit the first-order model, and out-capsule residues of chlorpyrifos in soil were maintained at 1.76 （±0.33） and 5.92 （±1.20） mg/kg in the period between 15 and 60 days, respectively. The degradation kinetics of CPF-EC fit the first-order model, and the residual periods of 5 and 20 mg/kg treatments were 60 days. Bacterial community structures in soil treated with two concentrations of CPF-MC showed similarity to those of the control during the test period, as seen in the band number and relative intensities of the individual band on DGGE gels （p 〉 0.05）. Fungal community structures were slightly affected in the 5 mg/kg treatments and returned to the control levels after 30 days, but initially differed significantly from control in the 20 mg/kg treatments （p 〈 0.05） and did not recover to control levels until 90 days later. The CPF-EC significantly altered microbial community structures （p 〈 0.05） and effects did not disappear until 240 days later. The results indicated that the microcapsule technology prolonged the residue periods of chlorpyrifos in soil whereas it decreased its side-effects on soil microbes as compared with the emulsifiable concentration formulation.