HORTICULTURAL DIVISION 707 



of water. This should be done just after the buds burst and again two 

 weeks later. Rainfall soon after spraying may make necessary a third and 

 a fourth application. 



THE WHITE MARKED TUSSOCK MOTH. The caterpillar of the white 

 marked tussock moth is one of the worst defoliators of deciduous park and 

 shade trees. The caterpillar, when full grown, is more than one inch long, 

 with a red head, two long black plumes back of the head and one long 

 black plume at the rear, four yellow brush-like tufts in a row on the back 

 behind the front pair of plumes and two red spots between the tufts and 

 the last black plume. The caterpillars hatch from the overwintering eggs 

 in April and May and immediately begin feeding on the leaves. When full 

 grown they seek a more or less sheltered place to spin their grayish cocoons 

 of silk and hair, from which the adults shortly issue. The male is a grayish 

 winged moth that flies, the female is short, stout and white, has very small 

 wings and is unable to fly. She crawls to the outside of her cocoon or nearby 

 and after fertilization lays her eggs in a white, froth covered mass and then 

 dies. Two or three generations of this species are usually produced annually. 



The species may be controlled by spraying infested foliage with lead 

 arsenate, one pound of powdered lead arsenate to fifty gallons of water, 

 and by destroying egg masses and cocoons. 



Spraying machinery suitable for performing the various necessary tasks 

 in insect control is on the market. Many types are available, each designed 

 to meet a special need for service and for cost of equipment. In the manage- 

 ment of extensive parks, motor driven spraying apparatus is desirable. 

 These machines should be equipped with large tanks for the insecticide 

 and powerful engines and pumps. Large tanks require less frequent filling 

 and therefore more trees can be treated in a given time. Powerful engines 

 and pumps assure maintenance of high pressure, thus ensuring the covering 

 of tallj heavy-foliaged trees. For the smaller parks, barrel or wheelbarrow 

 machines with long rods and hose, platforms and ladders, will often be 

 found very serviceable, and the initial cost of such apparatus is much less 

 than that of power outfits. 



