MSc

Detailed investigations were made on the entomogenous
fungus Fusarium pallidoroseum (cooke) Sacc infecting cowpea aphid
Aphis cracclvora koch.
Field studies showed that spore suspension and wettable
powder formulations were equally effective in controlling the pea
aphid. 7 x 106 spores per ml suspension in water or a similar
suspension of a wettable powder or quinalphos 0.05 per cent were
found to be equally effective in controlling the aphids under
field conditions. Spore suspension containing 3.5 x 106 spores


per ml have shown similar results during the later half of the
experimental period.
Pot culture studies conducted to assess the influence
of host plants of aphid on the efficacy of the pathogen revealed
that there was no influence of host plant on the pathogenecity of



F.


pallidoroseum.


The germination and viability of F.



pallidoroseum in formulation was found to decrease with increase
in storage period and the formulations retained its capacity for



germination and viability for more than ten months under
refrigeration.


The fungus was found nonpathogenic to vegetables viz.



as bhindi, brinjal, amaranths, tomato, chillies,


snakegourd,

bittergourd and medicinal plants, viz., adathoda, ocimum and notchi
under field conditions. Besides it was found safe to




natural enemies of aphids viz., Coccinella


septumpunctata,



Menochilus sexmaculata and Scymnus sp. The productive insects,
honey bees and silkworms were not at all affected by this fungus.
Cross inoculation studies using this pathogen showed
that three species of aphids, viz., Toxoptera aurantii, Aphis
gossypii and Aphis malvae were not infected.
A strain of F. Pallidoroseum isolated from a weed plant water hyacinth(Eichhornia crassipes) was found to be non pathogenic to the aphid Aphis Crassivora. Similarly F. Pallidoroseum was observed non pathogenic to water hyacinth. These observations indicated that the above two strains of F. Pallidorosem are entirely different.