Development Of Botanical Complex Synergistic Acaricide

Over the years, agricultural pest mites have been doing great damage to flowers, tea and various crops, which causes economic losses to China's agricultural production. The existing acaricides are mainly chemical acaricides and after long-term use it not only causes mites resistance, but also a serious threat to environmental safety and human health. In view of the features that botanical pesticides have, low toxicity, crops and operators safety, it is highly possible that it could be an important new direction of pesticide development. Previous studies showed that many botanical substances, such as Stellera chamaejasme extracts, some essential oils, etc. have acaricidal bioactivity, but these studies focused mainly on bioactivity and component identification rather than product development. In this paper, 63 substances from plants were screened for acaricidal activity and based on the screen result a successful formulation was finally developed. A systematic research of acaricidal bioactivity was carried out by a combination of virulence indoor tests and field efficacy trials, the specific results are as follows:1,Using carmine spider mite as test object, slide dip method as bioassay method, the result showed that substances from 63 species of plants had acaricidal activity. After primary and secondary screening, 6 plant substances rotenone.2,After synergistic test of these 6 selected substances, three synergistic mixtures rotenone and Z1, rotenone and Z2 and Z1 and Z2 were found and finally the best synergy ratios between them were determined. Co-toxicity coefficien(tCTC)of these three synergistic mixtures are 698.63,654.36 and 632.85 respectively which were mixed in the proportion of 1 to 8,1 to 12.5 and 1 to 1.5.3,According to the screening test of environment-friendly solvents and surfactants the eligible formulation of the three synergistic mixtures EC named LS-1,LS-2 and LS-3 were established and they all reached the EC miticide quality requirements.4,Field efficacy trials to carmine spider mite and hawthorn spider mite indicated that there are two synergistic mixtures showed higher control efficacy. With preparation diluted 500 times the control efficacy reached over 85% after a week and had some persistent period, being the same effect with 1.8% Avermectin EC which means good value in applications.