Study On The Activity And Distributivity Of 0.05 Percent Clothianidin·Cinnamon Leaf Granule In Cabbage And Soil

This paper proposes the idea that the cinnamon leaf powder could be used as the carrier, mixed equality with clothianidin technical material, prepare a new plant source granules, which was mainly used to control soil insect, and sucking mouthparts pests like aphid and bemisia tabaci. The single application of 0.05% granule clothianidin mixed in dry powder of cinnamon leaves, a novel formulation with time-saving and work-saving, was used to control pests in vegetables under a high dose. In this paper, the main volatile compounds were also determined from dry powder of cinnamon leaves by GC-MS. This paper studied biological activity of cinnamaldehyde and clothianidin for the second instars of scarab, analyzed the content and distributivity of cinnamaldehyde and clothianidin in soil and cabbage samples using HPLC, studied the way of active ingredient entering into soil, in the end, evaluated the safety of clothianidin and dry powder of cinnamon leaves in soil.The results of the determination by GC-MS showed that cinnamaldehyde was the foremost and accounted for 54.03% of the volatile compounds from dry powder in cinnamon leaves.The biological activity of cinnamaldehyde and clothianidin for the second instars of scarab were studied. The results showed that both of the two active ingredients have obvious lethal effects on the grub in certain concentrations, and also cause water loss and body color browning and significantly reduce the walking ability and drilling ability of the second instars of scarab. In addition, cinnamaldehyde also showed good repellent and fumigant activity against the second instars of scarab.The effects of simulated precipitation on the contents and distribution of cinnamaldehyde and clothianidin in soil were studied, finding that cinnamaldehyde in cinnamon leaf and clothianidin enter into soil with increase of time. The contents of peak of cinnamaldehyde and clothianidin in 0-5 cm soil would reach after 1 d treatment, and then would decrease. The reaching peak time of 10-15 cm and 15-20 cm would later, and the content was significantly lower than 0-5cm and 5-10 cm. In addition the dynamic degradation of cinnamaldehyde and clothianidin in soil were studied. The results showed that cinnamaldehyde and clothianidin with short half-lives degrading rapidly in soil were readily biodegradable pesticides, and the degradation rate of cinnamaldehyde and clothianidin in soil would decrease with increase of the soil depth.This paper studied the contents and distribution of clothianidin in cabbage under different field experiments, different growth period of cabbage(seedling stage and heading stage), different ways of applying clothianidin(spraying and broadcasting granules), and different light conditions(nature condition and dark treatment). The results showed that after spraying, more clothianidin was detected in leaf than in rootstock of the cabbage in seedling stage, while the content of clothianidin in heading cabbage reduced from outer to inner layer; after applying the clothianidin granules, clothianidin has the property transmitting to new leaves in cabbage of seedling stage, however, the content of clothianidin in heading cabbage reduced from outer to inner layer. The degradation rate of clothianidin varied significantly in different parts of cabbage under diverse conditions, the varying pattern of the degradation rate are as follows: nature condition> dark treatment, spraying> broadcasting granules, the upper leaves>the lower leaves>the rhizome tissue, the outer leaves>the inner leaves.This study copmopared the control efficiency against cabbage aphids and bemisia tabaci between 0.05 percent clothianidin · cinnamon leaf granule and 48 percent clothianidin suspension concentrate(SC), the former showed longer effective period, while the latter has stronger rapidly available.The toxicity of dry powder of cinnamon leaves and clothianidin to soil microbes were studied. The results showed that the respiration inhibition rates of 500 ?g/ml clothianidin in soil for soil microbial was less than 50% after 15 d treatment. It meant that clothianidin was low toxicity to soil microbial. However, the soil mixed 0.99% dry powder of cinnamon leaves showed high toxicity to soil microbial, after 2 d treatment, the respiration inhibition rates could be more than 50%, then decreases rapidly, on the contrary, after 15 d treatment, which could promote the respiration. Thus, considering the dose and time could make better use of cinnamon leaves.The single application of 0.05% granule clothianidin mixed in dry powder of cinnamon leaves, the active ingredients enter into soil through eluviations, both of them could be used to control the soil insect, while clothianidin could be absorbed and transmitted to cabbage to control the aphis and Bemisia tabaci, and both of them were safe with short half-lives belonging to readily biodegradable pesticides and low toxicity to soil microbial. When applying pesticides in different formulations and methods, not only we should consider the control effect, but also pay attention to the persistent and distribution of active ingredients in plants, which could provide scientific basis for residual toxicity and safety evaluation on residues.