APPLE GROWING IN CALIFORNIA. 89 



Apple Tree Leaf Roller. 

 (Archips argyrospila.) 



In The Monthly Bulletin, Vol. II, No. 9, of the State Commission of 

 Horticulture, the author published an illustrated article on this pest, 

 telling of its habits and occurrence in the state. The adult is a yellow 

 moth about the size of the codling moth, with white markings. Eggs 

 are laid in oval shaped masses, each containing from ten to one hundred 

 and fifty eggs, on the limbs and trunk in July. These hatch in the 

 spring as buds are opening and the little whitish larva? immediately 

 begin feeding and, if plentiful, serious destruction of blossoms and 

 defoliation of trees may result. 



AY hen full grown or about three fourths inch in length the larvae 

 pupate, mostly in the rolled leaves, though frequently elsewhere. 



Complete control may be brought about by an early spring applica- 

 tion of either a miscible oil spray or crude oil emulsion to kill the eggs. 



Apple Tree Tent Caterpillars. 

 (Malacosoma disstria and MaJacosoma americana.) 



The former is the common species in California. Both may be 

 recognized by the large web tents which are made where the colonies 

 feed, after hatching from eggs which were deposited by the moths on 

 the twigs the previous fall. These eggs are laid in masses encircling 

 the twigs and are easily recognized from those of other pests because 

 of this fact. Feeding usually takes place by the hairy caterpillars in 

 quite definite areas within and surrounding the tents. 



Control measures consist in removal of the egg masses when trees are 

 being pruned in the dormant season, destruction of the web tents with 

 the larva? enclosed in the early 'morning or late in the evening, and 

 arsenical sprays. Where spraying is done to control codling moth 

 tliis pest is also satisfactorily controlled. 



Tussock Moth. 

 (Hemerocampa vetusta.) 



Considerable injury is sometimes done to young apples by tussock 

 moth larvae, and mature fruits are often seen in the packing-houses 

 which show the scars due to this early injury. 



Like the canker worm moths, the females of this species are wingless. 

 The winter season is spent on the trees in the egg stage, in masses 

 protected by the ooeoons from which the female moths emerged. 



The larvae are quite resistant to an arsenate of lead spray, but 

 arsenite of zinc is said to be somewhat more effective. Sticky bands 

 are often used about the trunks of the trees to keep larvae, which are 

 shaken to the ground by jarring, from crawling back. 



Spring and Fall Canker Worms. 

 (Paleacrita vernata and Alsophila pometaria.) 



These two >prcirs of moths are very similar in appearance, both 

 being wingless and depositing their eggs on almost any portion of the 

 tree after crawling up the trunk. The larvae are some of the so-called 

 nn'iisurinu: w< rms. the spring species having cnly two pairs of prolegs 

 while the fall species has three. Otherwise they are very similar. 

 There is only one generation of each durinir the season. The spring 



