duces during the late spring, summer, 
and early fall. Reproduction is 
greater during the spring and fall 
than during the summer when tem- 
peratures are high. In warm, south- 
ern climates it is active during the 
entire year and reproduces except 
during periods of severe cold or 
when there is a lack of suitable food. 
In early spring almost all aphids 
are wingless females. As the season 
advances, and the population be- 
comes large and the food supply 
less succulent, winged females 
develop. These migrate to 
fields of alfalfa or other legumes. 
(Winged aphids are poor fliers, but 
can be carried long distances by 
the wind.) 
These females can reproduce with- 
out mating. They can produce from 
1 to 14 young per day during the 
reproductive period of their lives. 
In southern climates, 12 to 15 gen- 
may be produced in a 
other 
erations 
single year. 
During the fall in northern lati- 
tudes, true sexual forms develop. 
The males are usually winged and 
the females wingless. These mate 
and the females lay eggs. The eggs 
are glued to alfalfa leaves and stems: 
they are yellow-green when first laid, 
but soon turn shiny black. 
Pea aphid eggs are able to survive 
low temperatures that kill all other 
forms (although in some areas all 
forms may survive a mild winter). 
The eggs hatch in April or May, the 
time depending on the latitude. 
CONTROL WITH 
INSECTICIDES 
Spray with an insecticide before 
the aphids have damaged the alfalfa. 
One application per season, either by 
ground equipment or by aircraft, 
usually gives satisfactory control. 
For best results, spray when tempera- 
ture is above 60°. 
Use one of the emulsifiable concen- 
trates listed in the accompanying 
table. 
amount of water your sprayer is cali- 
Mix the concentrate with the 
brated to deliver per acre (not less 
than 6 gallons for ground equipment, 
and not less than 2 gallons for air- 
craft equipment). 
CONCENTRATES FOR PREPARING SPRAYS, AND RATES AT WHICH THEY 
ARE APPLIED 
Insecticide (as emulsifiable concentrate) 
and strength 
Demeton, 25 percent............................. 
Diazinon, 25 percent............................. 
Malathion, 97 percent............................ 
Naled, 8 pounds per gallon..................... 
Parathion, 25 percent... 
Mevinphos (Phosdrin), 25 percent............. 
depp, 20percent............................, 
Amount of emulsifiable concentrate 
to be added to water to treat | acre 
Pints 
] 
— 2 
lito T¥e2 
