~J- 
m@ per liter for 70 or 75 minutes seems to be the critical point. A mean 
concentration of 4.0 m g per liter for 60 or 70 minutes would be as low as 
could be safely depended upon for control of insects and mites. Under the 
conditions existing in mushroom houses during the peak of heat it is apparent- 
ly impossible to obtain the necessary concentratione" 
Retarded larval phases of the narcissus bulb flye--C. Fe Doucette, 
reporting on investigations of the larger narcissus bulb fly (Merodon 
equestris Fabe) says: "Emergences have been recorded during May from larvae 
definitely known to be of 1942 origin; 24 males and 18 femles have emerged, 
indicating that retardation does not involve a sex factor. The color com= 
binations of these adults vary as ih normal adults, indicating that there is 
no. special color variety or strain involved. The emergence period corre= 
sponds closely with that of normal adultse" 
Calcium cyanide effective against Mexican mealybug.e--He He Richardson, 
continuing his studies on the effectiveness of overnight' fumigations with 
calcium cyanide for the control of Phenacoccus gossypii Te & Ckll. on chrysan~ 
themums grown under glass, confirmed the results of previous experiments 
which indicated tht 1/4 ounce dosage will apparently produce a very high 
kill of adults and nymphs, as well as of a large percentage of the eggs. A 
second fumigation within a week a@ two produced complete kill of the insects 
‘surviving the first funigation. Apparently a dosage of 1/4 ounce is nearer 
the upper limits of tolerance of chrysanthemum stock plants although, when 
the plants were thoroughly dried (not watered for 30 hours prior to fumigation), 
no injury occurred. 
Machine developed for atomizing oils in the field.--The Madison, Wise, 
laboratory is developing an atomizing machine for use in pea aphid control. 
The machine consists of a 4ehorse power aluminum engine weighing 90 pounds; 
a 2-cylinder compressor of 12 cubic feet capacity per minute, made of aluminum 
and weighing about 75 pounds; a 5~gallon air-compression tank; and a 4«gallon 
oil tank, On the oil tank is mounted an oil filter, such as is used on a 
furnace oil burner. On the boom are mounted 12 nozzles designed by Te He 
Bronson during the winter months. Compressed air and oil under pressure are 
delivered to each nozzle. The whole outfit is mounted on a light 2-wheel 
trailer and by means of angle irons the trailer is made into a hood 14 feet 
and 10 feet wide, which confines the atomized oil while it is circulating 
among the pea foliagee 
CEREAL AND FORAGE INSECTS 
Status of hessian fly in south-central Pennsylvania.--Daily observa- 
tions by J. Se Pinckney at Carlisle, Pa., showed that the oviposition period 
of the flies of the spring emergence of Phytophaga destructor Say in the 
vicinity of Carlisle began on April 19, reached its height between April 26 
and May 9, and was practically over by May 14, although a few eggs were found 
until May 24- Surveys by Je Se Pinckney and E. J. Udine of hessian fly 
abundance in New York and in Adams and Perry Counties in Pennsylvania showed 
heavier infestations than were expected. In 12 fields examined the minimum 
infestation was 2 percent, the maximum 40 percent, and the average 21 percent. 
The culm was used as the unit of examinatione 
