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Insects and Their Control 
Tarnished Plant Bugs 
The tarnished plant bug or sting fly comes into the 
greenhouse through open doors and ventilators in late 
summer or early fall and does considerable harm to 
this crop. Chrysanthemums growing in the open are 
frequently affected. Varieties such as Mary L. Hall 
and Sea Gull are attacked to a greater extent than 
other varieties. 
INJURY. It has sucking mouth parts and obtains its 
food by inserting its long, slender beak into the 
plant tissues and sucking up the contents of the in- 
jured cells, apparently injecting saliva, which causes 
the death of the tissue in the immediate vicinity. 
The stem is often slightly bent, and the terminal 
growth is malformed because of this injection. 
CONTROL. Early morning spraying or dusting with 
any of the pyrethrum materials will kill those bugs 
that are present but this will have to be done each 
day for complete eradication. Deenate 50W has 
been giving fair control, but again this insecticide 
is best used as a contact. Parathion fumigation will 
control this insect in the greenhouse. 
Termites 
Termites are not ants, though often called white ants. 
The food of termites is wood or cellulose. Soil inhabit- 
ing forms are the most common in the greenhouse. 
INJURY. Termites sometimes injure chrysanthemum 
plants by working up the center of the plant and 
Tarnished Plant Bug 
hollowing out the stem. This injury will eventually 
kill the plant. 
CONTROL. Clean up all wood debris in soil. Replace 
old wooden benches. Keep wooden bench supports 
from direct contact with the ground, 
Thrips 
The chrysanthemum is usually attacked by one or more 
species of thrips. These small, narrow-bodied, active 
insects which range in color from yellow to brown or 
almost black, injure both the leaves and the blossoms. 
Thrips are a real threat to Florida mum growers. 
INJURY. Thrips have mouth parts that are fitted for 
piercing and scraping the leaf surface and for suck- 
ing the juices and other cell contents. The upper 
surface of the foliage is covered with whitish blotches, 
while minute black specks appear on the lower sur- 
face. Unless a constant watch is kept on the plants 
and control measures are properly executed, thrips 
are capable of causing severe injury within a short 
time. 
CONTROL. Deenate 50W used at the rate of | 
pound to 100 gallons of water is a very effective 
control. Other insecticides containing Lindane are 
also recommended. Parathion will control the 
chrysanthemum and onion thrips. Regular dustings 
or spraying are necessary where infestation is heavy. 
Chlordane is also very effective. 
Adult Onion Thrip 
Thrip Injury 
71 
