Feb. 26, i 9 i7 Squash Disease Caused by Choanephora cucurbitarum 327 
squash plants, were placed in test tubes washed in a small quantity of 
water, and the wash water was examined by placing drops of this water 
on a microscopic slide. Conidia were quite commonly present in this 
water. The striped and spotted cucumber beetles (Diabrotica viitata and 
D . punctata , respectively) were also found to be carriers. The wind is 
also an agent in the dissemination of this fungus, as determined by a 
series of 13 agar plates which were exposed in a field of squashes on the 
morning of July 11. On the following day C. cucurbitarium had developed 
on all of these plates. 
SUMMARY 
(1) Choanephora cucurbitarum is parasitic upon summer squashes, 
causing a blight of the flowers and a rot of the fruits. 
(2) The disease has been the cause of very considerable losses during 
the past summer. 
(3) Infection of fruits occurs, for the most part, by the passage of the 
fungus from the fading corolla to the young squash. 
(4) Various species of bees, striped and spotted cucumber beetles, and 
currents of air are agents of dissemination of the conidia. 
(5) The fungus has been found on languid flowers of cucumber, althea, 
okra, cotton, and other malvaceous plants. 
(6) C. cucurbitarum is the only known American species of this genus. 
(7) The conidial stage alone appears on affected parts of the several 
host plants. 
(8) Sporangial, chlamydosporic and zygosporic stages have been 
developed in artificial culture. None of these stages have previously 
been reported by investigators within the United States. 
(9) All of the reproductive stages have been noted in the same culture 
on nutrient agar. Conidia, sporangia, and zygospores may mature in 
cultures 24 to 48 hours old. No decrease in luxuriance of asexual fructi¬ 
fication has been found in culture on nutrient agar. 
