Insects as Possible Distributors of Phymatotrichum Root Rot

SUMMARY

A number of insects were placed in screened cages in the laboratory, where they were fed on strands and on cotton roots freshly infected by Phymatotrichum root rot. The fecal pellets and some of the insects themselves were cultured on potato-dextrose agar in Petri dishes, but Phymatotrichum growth was not obtained from any of these cultures.

A number of insects were fed on cotton leaves which were dusted with a heavy coating of the spores of P. omnivorum, while others were fed on a sweetened solution containing a heavy suspension of Phymatotrichum spores. No growth of P. omnivorum was obtained from any of the cultures made of the fecal pellets or the entire insects thus fed. None of the insects used in these experiments could be induced to feed on the sclerotia of the fungus. From these preliminary tests it appears that insects are probably not involved in the spread of Phymatotrichum root rot.