protection of rubber wood from insect borers - Kerala Forest ...

More documents

Recommendations

Info

Field trialsObservations made each month for a period of one year on treated samplesstacked along with converted rubber wood in the storage yards ofindustrial units at Ollur and Kodumon showed absolute deterrence oftreated veneers to borers. With regard to fungal attack, only the treatmentswith Chlorothalonil were free from fungal attack and the results indicatethat the treatments 14 and 15 (Chlorpyriphos/Fenvalerate withChlorothalonil) were the most effective.The results obtained in the control were also interesting in that no insectbuild up had occurred. While in the first experiment using planks thecontrol samples were heavily attacked by S. anale within a few months, noinfestation was noticed in the experiment using veneers. It may be pointedout here that in our trials using planks, the control samples were notsubjected to treatment in water whereas in the trials using veneers thecontrol samples were kept immersed in water and then dried in the air.Since the veneers are thin, treatment in water must have resulted in theleaching out of soluble sugars and starch which are known to attractinsects to initiate infestation. Water treatment of sawn timber may behelpful in preventing borer infestation and this aspect is worth exploring.Retention of chemicals in treated rubber woodThe quantity of chemicals retained in the treated wood is a factor thatexplains the deterrence to bio-degradation. Core loading of 0.2% boric acidhas been shown to provide protection of treated wood from insect borers.In order to attain this the overall dry salt retention should be about 1%(McQuire.1962). Rubber wood treated to an overall retention of 0.4 %BAEwas found to give protection against S. anale (Gnanaharan et al, 1983)and along with NaPCP, against termites (Varma and Gnanaharan, 1989).The solution pick up and chemical retention with various chemicals usedin this study are given in Table 7. The solution pick up ranged from 101l/m3 (Boric acid 5%) to 129 l/m 3 (Chlorpyriphos 0.2%). There was no cleartrend in solution pick-up which may be due to the difference in viscosity ofsolutions. Fifteen minutes immersion was found to be enough to attain asolution pick-up in the range of 100-130 l/m 3 .14
Table 7.Basic characteristics of solution pick up and chemicalretention in different treatmentsNo.-1TreatmentsChlorpyriphos 20 ECConcentration(A)(0.1%)Solutionpick-upl/m3 (B)07.6 1Retentionkg/m 3AxB0.102Chlorpyriphos 20 EC(0.2%)28.990.253Chlorpyriphos 20 EC(0.5%)16.950.584Fenvalerate 20 EC(0.01%)08.430.0 15Fenvalerate 20 EC(0.05%)109.680.056Fenvalerate 20 EC(0.1%)116.410.117Cypermethrin 25 EC(0.01%)102.960.0 18Cypermethrin 25 EC(0.05%)105.600.059Cypermethrin 25 EC(0.1%)113.790.1110Boric acid(3%)106.463.1911Boric acid(5%)101.375.0612131415Boric acidBoric acid +Chlorothalonil 75 WPChlorothalonil 75 WP +Chlorpyriphos 20 ECChlorothalonil 75 WP +Fenvalerate 20 EC( 10%)(3%)(0.5%)(0.5%)(0.5%)(0.5%)(0.1%)108.72114.22117.38119.4110.873.991.170.7116Control (Water)116.530Similarly the chemical retention ranged from 0.0 1 kg/m 3 (Cypermethrin0.01%) to 10.87 kg/m 3 (Boric acid 10%). The difference in retention wasmainly because of the chemical and the concentration used. In this study,it was seen that even the lowest concentration tried gave effectiveprotection. Therefore, the threshold values for these chemicals will belower than that of the lowest concentrations tried. As all the treatmentswere effective, statistically it is not advisable to compare retention of onechemical in rubber wood to that of other chemicals. As the veneers arethin, retention of the retained chemical would be uniform. However, thiscannot be expected in thicker sections. However, when thicker sections aretreated commercially, at least the lowest concentration of differentchemicals tried should be used.15
Page 2 and 3: CONTENTSPage FileAbstract 1 r.189.2
Page 5 and 6: etc. The beetles are brown in colou
Page 7: (Platypus solidus Wlk. and P. latif
Page 10 and 11: undle was exposed to laboratory bre
Page 12 and 13: of the sample and is expressed in t
Page 14 and 15: Table 5. Insect activity recorded i
Page 18 and 19: CONCLUSIONSnsect attack coupled wit
Page 20: McQuire, A. J. (19621. Stain and mo

protection of rubber wood from insect borers - Kerala Forest ...

Create successful ePaper yourself

Delete template?

Save as template?