64 MASS. EXPERIMENT STATION BULLETIN 233 



under them anytime during the winter. Experiments show that about one- 

 third of the worms can be destroj^ed in this way, the number depending 

 on the thoroughness with which the scraping and examining is done. Do 

 not put bands on your trees unless yoti kill the xcorms xinder them. 



Bait Traps. Codling moths are not attracted to lights as are many insects. 

 They may, however, be attracted to certain odors. Recent experiments in 

 the Northwest have shown an increased control of 12 to 15 per cent where 

 pans of fermented apple juice were hung in trees in a sprayed orchard. Such 

 baits are most effective during the maximum flight of the moths which in 

 Massachusetts occurs from May 15 to September 1. Pans or wide-mouthed 

 pails or jars are used for containers, and the bait must be kept uniform by 

 cleaning out debris and renewing to prevent evaporation and dilution. Baits 

 for the codling moth have not been thoroughly tested in this State and are 

 recommended as an experiment only. 



Disposal of Cull Apples and Protection of Storage. Worms in cull apples 

 are often the means by which damaging infestations are carried over from 

 year to year. To avoid this, pick all fruit from the trees and ground, and 

 dispose of it quickly. Storage bins at cider presses often harbor large 

 numbers of worms. The bins should be built with a minimum of cracks 

 and thoroughly cleaned during the winter. Many worms spin winter cocoons 

 in boxes, barrels, and parts of the packing shed. It is important to keep all 

 windows, doors, and other openings in the packing shed and storage house 

 screened or closed during the spring and summer. Boxes and barrels 

 should be stored in a "moth-tight" place. One instance is known where 

 more than 3,600 codling moths were collected during the summer at the 

 windows of a shed containing about 1,000 empty boxes. In addition to in- 

 creasing the infestation in the orchard, moths emerging from larvae winter- 

 ing in a shed usually appear later than those in the orchard, and seriously 

 interfere with effective control by spraying. 



Spraying. 



Materials. Lead arsenate is the most satisfactory insecticide for the 

 control of the codling motli. It is manufactured both as a powder and 

 as a paste. Either one is effective when properly used. The powder is 

 more conveniently handled and cannot freeze or dry out. 



Arsenic oxide is the active agent in lead arsenate, and Federal stand- 

 ards require at least 12.5 per cent of this in the paste and 25 per cent in 

 the powder. These requirements are so m'cII guarded, especially in brands 

 which enter interstate conunerce, that the fruit grower may be assured 

 that his lead arsenate contains the necessary amount of active poison. 



The quantity of lead arsenate to be used for spraying is calculated for 

 the powder form, and, when the paste is used, twice the amount by weight 

 is always necessary to obtain the same quantity of active poison. 



To control the codling moth, one and one-half pounds of lead arsenate 

 powder in each 50 gallons of water is recommended. In many parts of the 

 country, one pound in 50 gallons has proved sufficient but because of the 

 presence of otlier pests, such as the plum curculio and the gypsy moth, a 

 greater amount of poison is considered advisable in this State. 



Calcium arsenate, magnesiimi arsenate, zinc arsenite, and Paris green have 

 been used for codling moth sprays but they are either less effective, more 

 expensive, more injurious, or less available than lead arsenate. 



