Study On The Efficacy Of New Baits To Control Termites

Termites are ancient social insects. Although termites'body is small, the destructions generated by them are very horrendous. They cause damage almost in every economic domain in China. The direct economic losses that termite caused were estimated at 2-2.5 billion RMB annually in our country. The cryptic damage caused by termites was hard to estimate. The latter half of last century, chlordane and mirex as longlasting and inexpensive insecticides were used popularly in termite control industry. But these chemical insecticides have great harms to environment and human being compared to the advantages they generated. These two persistent organic pollutants have been listed in the elimination listing of Stockholm Convention on Persistent Organic Pollutants in May 22,2001. The convention appeals the signed countries to ban the production and use of chlordane and mirex as soon as possible. Therefore searching safe and friendly environmentally alternative control methods play an important role in termite control. Termite monitoring control system is a friendly environmentally control method and is in agreement to the idea of termite IPM. In our studies, we tested two kinds of termites (Reticulitermes chinensis and Coptotermes formosanus) and evaluated the control efficacy of five baits against these two termites. We also studied the ecology of these two termites in field. In addition, we studied eliminating efficacy of five termite baits to whole colonies of these two termites in field. Major research results are as follows:(1) Estimation of foraging population size of termite colony:test results indicated that the foraging individual number ranges from 17422 to 158731 for R. chinensis colonies and from 61745 to 2427089 for C. formosanus colonies. The territory of termite colony activity ranges from 0.15 m to 2.10 m for R. chinensis colonies and from 6.00 m to 64.50 m for C. formosanus colonies. The amount of wood consumption of termite colony:The test results indicated that the amount of wood consumption from August to October in 2009 ranges from 0.91 g to 21.33g for R. chinensis colonies and from 5.23g to 428.99g for C. formosanus colonies.(2) Eliminating efficacy of five kinds of baits to termitesThe 0.5%hexaflumuzon bait can eradicate termite colonies completely. The average amount of baits that eradicated R. chinensis was about 93.6g/colony and the needed time ranges from 152 d to 305 d. The amount of baits that eradicated C. formosanus was about 562.5g/colony and the needed time ranges from 244 d to 335 d.The 0.1%chlorfluazuron bait also has good eradication effectiveness to termites. Ample baits can eliminate all colonies completely. The average amount of baits that eradicated R. chinensis colonies was about 107.0 g/colony and the needed time ranges from 152 d to 335 d. The average amount of baits that eradicated C. formosanus colonies was about 332.0 g/colony and the needed time ranges from 305 d to 335 d.The 0.1%triflumuron bait could eliminate termite colonies completely. The average amount of baits that eradicated R. chinensis colonies was about 82.5 g/colony and the needed time ranges from 244 d to 305 d. The average amount of baits that eradicated C. formosanus colonies was about 483.3 g/colony and the needed time ranges from 244 d to 335 d.The 0.08%sulfluramid bait only eradicated part of colonies. Main reasons generated this result had two One was bait became mould easily. During the rainy days, the soil was very moist. The baits are likely to mould and termites refused to feed mould baits. Another was bait was repellent to termites. This bait has obvious repellence to termites when it was applied but termite would feed this bait after the active ingredient in bait decreased to certain concentration.The 0.0025%imidacloprid bait only eliminated part of colonies. This bait has some shortages:(1) the bait can only be applied at the weather that has no rain for a long time. Because under this weather condition, the humidity of weather is relatively low and the bait goes mould slowly, termites can feed on these baits. (2) The active ingredient concentration of each bait cake is different. We found some baits have obvious repellency to termites during the period of our test. This phenomenon suggested the active ingredient in the bait cake exceed the concentration that termites accepted.