THE MONTHLY BULLETIN. 239 



CALENDAR OF INSECT PESTS AND PLANT 



DISEASES. 



By E. J. VosLER, Assistant Superintendent, State Insectary- 



[Under the above heading the author aims to give brief, popular descriptions and 

 methods of controlling insect pests and plant diseases as near as possible just prior 

 to or at the time when the suggestions given should be carrietl into effect by the 

 growers.] 



DECIDUOUS FRUIT INSECTS. 



The Red-Humped Caterpillar. 



The red-hnmpod caterpillar causes considerable destruction to the 

 foliage of the walnut, apple, prune, plum, and cherry. The cater- 

 pillar is easily recognized by the coral red hump on the fourth seg- 

 ment. The head is reddish in color, and the body is striped with 

 slender bands of black, yellow and white. There are two rows of 

 prominent black tubercles along the back. These caterpillars are 

 abundant during June. July, August, and part of September. Hand 

 pick the young caterpillars Avhen they are clustered together on one 

 or tAvo leaves if possil)le. Of course, in large trees this would 

 be impracticable, and it Avould be necessary to spray the foliage 

 thoroughly with arsenate of lead, five pounds to 100 gallons of water. 



The Cherry and Pear Slug. 



The pear slug is known to the orchardist as a dark olive green 

 slimy worm, having the anterior portion of the body enlarged. It 

 strips the upper green surface from the leaves, which later turn 

 brow'U. This insect feeds on the pear, cherry, plum, quince, etc. It 

 is easy to control by l)lowing lime or dust upon the infested leaves, 

 or by spraying with the ordinary soap and emulsion sprays; also 

 arsenate of lead, four pounds to 100 gallons of w^ater. The latter 

 spray is slower in action, as the slugs must eat the poison to be 

 destroyed. The soap spray is made by first dissolving the soap, 

 preferably whale-oil, in hot water and then diluting it so that it is 

 applied at a strength of one half pound of soap to a gallon of water. 



Mites on Deciduous Trees. 



Several species of tiny mites attack the foliage on deciduous trees, 

 notably the almond, peach, and prune. The brow^n mite, which is 

 especially destructive to the almond, is reddish in the young stages 

 and brownish in the adult. It does not spin a web. Infested leaves 

 present a faded-out. spotted appearance. The two-spotted mite spins 

 a web which is easily seen. It also produces a spotted effect on the 

 leaves. It is usually of a greenish color with two dark spots on the 

 body. During the growing season dry sulphur is successful under 

 favorable weather conditions, i. e., when applied when dew is on the 

 trees. The atomic sulphur spray, one gallon of the atomic sulphur 

 to 30 or 35 gallons of water may be used. Lime-sulphur solution 

 during the growing period on deciduous trees is liable to cause injury 

 by burning. 



