GRASSHOPPERS need no description. Chlordane is very effective against grass- 
hoppers used as for Cucumber Beetles. Damage to dahlias can largely be prevented 
by spraying, or dusting, a wide area around the dahlia plot, thereby killing them 
before they get to the dahlias. No damage has been noted to dahlia foliage when 
this material has been applied to the plants, and when it is not practical to treat 
adjoining areas, the spraying of the plants will satisfactorily eliminate the grasshoppers. 
JAPANESE BEETLES which are very destructive to blooms, and their presence 
readily detected, can be controlled by DDT sprays. Treating the soil, in which the 
adult beetles lay their eggs, with DDT will destroy the grubs before they emerge from 
the ground in the spring. Five pounds of a 10% DDT per 1000 square feet is the 
usual recommendation. Lawns thus treated are not harmed. 
LEAF EATING INSECTS AND CATERPILLARS, whose presence is evident by their 
eating of foliage, readily controlled by spraying or dusting with stomach poisons such 
as arsenicals. DDT also seems to control, either as a spray or dust. 
LEAF HOPPERS are small greenish-yellow, flying insects which are very active in 
warm weather. Disturbing the plant will cause them to fly rapidly away and they can 
best be detected in this way. They are usually found on the under sides of the leaves 
sucking the plant juices, causing the edges of the leaves to turn yellow, eventually 
browning and destroying entire leaves at the bottom of the plants. Previous controls 
have not been very effective unless applied every two or three days. DDT will control 
them almost 100%. 
RED SPIDER MITE, or simply red spider, are very small black and white to brown- 
ish, minute insects, nearly always found on under sides of the leaves. A magnifying 
glass is necessary to see these tiny insects but their damage is apparent by browning 
of the lower, and to lesser degree, the upper surfaces of foliage. Under sides of the 
leaves usually appear to have “'rusty"’ areas and a sort of silky appearance. In the past 
they have not been serious pests of the dahlia except in isolated cases. However, if 
DDT is used as a control for other insects, it is likely that red spider mite will be very 
prevalent and cause much damage if not promptly controlled. To make matters worse, 
DDT kills the predators or parasites which normally feed on the mites. 
Parathion has proven very effective in the control of red spider mite when used 
at the rate of one half pound of 15% wettable powder to 100 gallons of water. If a 
dust is preferred, a 1% dust will give excellent results. This can be made by adding 
fourteen pounds of dusting talc to one pound of the 15% powder. Aside from the 
precautions to prevent contamination of the skin and clothing of the operator, it is 
close to ideal. No foliage burn or injury to blooms has been observed. Parathion 
may be used in DDT sprays or dusts, but should not be used oftener than necessary 
to keep red spider under control. 
TARNISHED PLANT BUGS are small plant bugs about a quarter of an inch 
long, brown mottled with shades of red and yellow. They are seldom seen on the plants 
as they fly away at the slightest disturbance. The bugs puncture the stalk, stems and 
buds, causing small black spots. Growth of stung part is severely checked, causing a 
shortening between nodes of the plant, shortening of stems, and causing buds to open 
one-sided or to fail to open at all. Badly infested plants are short, very bushy and 
never produce presentable blooms. DDT has proven highly effective in the control of 
this troublesome pest which has been very difficult to contro! before. 
THRIPS are very small, light greenish-yellow to dark brown insects which may be 
found by close examination of unfolded leaf tips and among petals of the flowers. 
A magnifying glass will aid in finding them as they are almost invisible to the naked 
eye. They cause malformed, dark spotted and blistered appearance of the leaves 
and often result in stunting of the plants. They are easily controlled with DDT. The 
Tarter Emetic and brown sugar spray, previously recommended, is still considered an 
adequate spray material. 
Considerable success in keeping down the ravages of pests has been obtained by 
some growers by frequent, over-head watering, during the hottest part of the day. The 
water is turned on for a couple of hours every two or three days. This method is more 
practical on light, well drained soils than on the heavier soils which may become 
saturated to the detriment of the plant. 
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