The application status of abamectin in china and its prevention research on termite
The application status of abamectin in china
Abamectin has no inhibiting effect on most of the fungi, bacteria and yeast; while it has good control efficiency on various animal gastrointestinal nematodes, animal lungworms, hypoderma bovis, lice, mites and ticks. Abamectin has stomach toxicity and contact action on the prevention of pests and mites. It also has weak fumigation action, no ovicidal action and systemic action. It has strong permeation on leaves which can be used to kill the pests under the epidermis and have longevity of residues. Currently, it is widely used in greenstuff, fruit trees, wheat, oilseed rape, tea, cotton, tobacco, edible mushrooms, garden flowers and other crops in china. It can be used to prevent red spiders, spider mites, diamond back moths, cabbage caterpillars, vegetable leaf miners, vegetable thrips, phyllonistis citrella staintons, pear psyllas, cotton bollworms, thrips tabacis and other pests. In addition, researchers have found that it also has good effects on the prevention of termites.
In the high toxic pesticide substitution demonstration project summing-up meeting in 2008, abamectin was recommended as the fourth batch of high toxic pesticides alternative which can be used in preventing rice stem borer, soybean pod borer, phyllonistis citrella staintons and apple leaf mites. In 2008, the abamectin produced by one of china’s famous pesticide manufacturer broke through its sales amount to 100 million Yuan, which causes the application of abamectin and its mixtures on the rice promoted by many enterprises in china.
According to the statistics, the registered abamectin products in china are about 3000 kinds, among which the active compounds are about more than 80 kinds, single dosage are about more than 1000 kinds and the rest are all mixtures. At present, the kind of products having the effective constituent of abamectin analogues which passed the registration in China’s Agriculture Ministry and used in the prevention of termites is called ibamectin, which can be disposed on the soil spraying and wood soaking and is produced by abamectin manufacturers.
The prevention research of abamectin on termites
Due to the good poison effect and convenient operation, using chemical agent to prevent termites is still the most popular technical method at present. However, the chemical agents will become a great threat to the environment and human health. Therefore, it is one of the main tasks and targets for termite research workers and technical staffs to find alternative methods. Biological has its specialty of high efficiency and safety, among which the biological control research on termites was carried out much in last decade. Many of the biont such as fungi, bacteria, nematodes and entomopathogenic organisms will have good effects on the prevention of termites in the laboratory test, while the effects are not very ideal in the field experiment. As a result, the biological agents used on the prevention of termites have fewer quantity and variety compared with other chemical agents.
The research about abamectin prevention effects on termites is carried out in recent years. By using poison soil method, filter paper method and toxic soil pillar method to measure the poison effect of 0.2 percents abamectin oil on reticulitermes flaviceps, Jianchu Mo found that abamectin has slower contact action on termites of which the LC50 value are all lower than 20mg/L after contacting or eating agentia 96h later; after spraying the soil with more than 25mg/L concentration of abamectin, it will prevent the termites from penetrating the toxic soil pillar. Wei Zhang and Shaonan Li measured the effects of the poison bait mixed with abamectin and bait and found that 20mg/kg concentration of poison bait can kill all the termites. Pingsheng Zhong and Zhiwei Huang measured the transmission toxic of abamectin, mirex, BT and other two agenita on Formosan termites, in which the results showed that after using imidacloprid in about 1-2 days, the death rates of Formosan termites were all more than 36 percents, while the effect of cartap is very slow by which the biggest death rate is 12.4 percents in 9th day. Abamectin and BT are similar with mirex, with which the peak mortality of termites will occur in 4-5 days after the drug and the death rates are all above 32 percents. The lethal dosage of abamectin on Formosan termites is 0.0312ug/only, which also has no pollution on the environment. From these research reports, we can see that abamectin has high toxicity on termites under the indoor conditions.
The tested coptotermes, reticulitermes and ergates will all die after continoually contacting with 0.3 percents of abamectin oil with the concentration of 100mg/L. However, if they only contact with the medicated paper filter for about 30 min, it will need 750mg/L and 1500mg/L concentrations of abamectin oil to kill all of them. When spraying ibamectin on the soil, it can completely prevent termites from penetrating 50mm thickness of poison soil and kill more than 90 percents of coptotermes and reticulitermes that contacted with the poison soil by spraying more than 350mg/L concentration of ibamectin.
The field test reports about the prevention of termites with this kind of drug are rarely to be seen. Therefore, by using poison bait of 100 mg/kg abamectin to conduct the field efficacy trials, in which the result shows that the termite frequency is obviously reduced (the reduce rate reaches to 80 percents). When spraying 5L liquid on every square meter of soil in the field, all the testing concentrations will be penetrated by the termites without covering; while under the covering conditions, only 1500mg/L concentration can successively prevent the termites from penetrating. Besides, after the medicine leaching woods are embedded into the field soil, only the woods having the concentration of 1500mg/L will not be decayed by the termites in 12 months. This shows that the effects of ibamectin on the prevention treatment of termites in the field should be further researched and improved.