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 grass- 
hoppers. 
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. ‘'Dowspray-!7'' 
applied according to manufacturer's directions has proven highly effective as a control, 
especially when combined with DDT. Dowspray-|17, as the name applies, is a spray 
material manufactured by the Dow Chemical Co., Midland, Mich. It seems far superior 
to all other standard red spider sprays. ‘'DN-269'' another DN compound has proven 
effective as a dust and much more effective than any previous dust for this purpose. 
Applications of spray or dust must be thorough and applied to the under sides of the 
toliage as well as the upper surfaces. If Dowspray-I7 is used, great care must be 
exercised to weigh the material accurately and to keep the material in suspension by 
vigorous agitation, while spraying. High pressure sprayers developing 200 pounds 
pressure, or more, are advisable as the material is applied more evenly and with less 
“runoff, thus eliminating the two chief causes of foliage burn. A third cause of 
foliage burn is the use of the material when temperatures are high. DN-269 is safer 
to use but must be applied at ten day intervals, and more care must be used to apply 
it lightly and evenly to infected areas (undersides of the leaves). NNOR may be 
used as an alternate material for the control of red spider; this in spray form. 
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. 
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