Biological Control of Termites with (a) Pheromones (b) Pathogenic Fungi

Abstract

Termites are one of the ?ost devostating pests of cellulose materials. Until recently, insecticides have been employed to erradicate the pests, but these chemical compounds are liable to damage plantation, animal life and have a short gun effect on benificial insects. Recently, pheromones have been safely employed to erradicate harmful insects, as in giypsy moth (Beroza, 1960; Beroza & Jacobson, 1963, 970; Beroza et al, 1971) and in oak iferanus {Uenary et al, 1973, 197, 1975) c iert i ca co nication syste sex a -1-rac a. s. ? ese ca r e

r.) ere _ec e ah an , rKers e?e seperc.?eci ::.--.:r: .• the na t e r i a L u s i ng v ac ui pump , ere reser e in n-penta.. e 9o/? arid stored at -10°c a c o o Lad .:. .. c ub a t o r until 3 0 gms of insec cs we ic c o LLe c t ed , The trail phe r omone wa s direct y extracted in n-pentane a?d biologically evaluatea. Thereafter, the workers were homogenized and again biologically evaluatedo Both biological evaluations were made through behav?ioural tests using workers, which showed positive response indic:.ting that a biologically active pheromone aas present. Bio-chemical analysis of the trail p.eromone was made by homogenizi?g 300 gms of workers, co-distillation/steam distilla?ion of the supernatant, column chromatography of the distilate. vifferent fractions thus obtained from column c ...ro. atography were s..10 · ected to t. in layer chro atogra h • _Le ma?e?&:- ??s s -?ec e ?o ra es s duri eac sage of

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subjected to Gas-liquid chromatography, which showed that a g 1 purified, biologically active material had been obtained. The chem a analysis showed that this material was un-saturated hydrocobons. Further studies are recommand?d to investigate the chemical nature of the phe?omone so as to synthesize it for biological control of the termitesQ A separate exten?ion research proposal is being submitted to carry on the studies. Part.B.

Alates and differently arranged batches of workers and soldie?s we?e kept in stcrelized petridishes over noist filter papers. Three cxtermally occuring patbogcns viz; Aspergillus niger !•?and !·f? were observed to cause mort?lity to termites.

Ac:, E._i£_e..£ caused mortality within 24 hrs. ?-? and !•fla.vus caused rnortali ty w.i thin 48 hrs o Sc ann i ng elec tro-micrographs show that mycellium penetrate through inter integumentary spaces, leg joints, between the.antennae segments. They also grow between the mouth parts. Behavioural studies indic.·te that on infection grooming and allogrooming activities ar? accelerated. On the contrary feeding, colony formation decline. Similarly, in alates courtship beh&viour also declines considerably. The patho?cns ere isolated and cultured in the culture cages for growth. Specific pathogenicity was confirmed by re-infection through spore walk of termites. It is speculat?d that mortality is cuased by toxins excreted by the pathogens. This was confirmed by using extracts of mycellium and spores obtained from french press cell brackero

Further studies are recommend8d to study the nPture of toxins usin electrophoresis, UaVo spectrometry and _different chromatography techniqu s Further histopathological & scanning electromicroscopic studies are also needed to have deep insight into the problem of pathogenicity and toxicity so that the patho?cns may in future· be employed as a vehicle to biological control of t?r?ites. A separate extension research proposal is being t for fut?re studies.