EXPERIMENT STATION BULLETINS. 



289 



CANKER WORMS. 



Apparently the worst insect of the apple orchards for the past few years 

 has been the canker worm. Many people have found the leaves in the 

 orchard turning brown and disappeariag almost as soon as the trees are 

 through blossoming. This is the work of canker worms. If one of the 

 limbs is jarred as soon as the work is noticed, many looping caterpillars, 

 such as are seen in the cut, will often suspend themselves in mid air, or drop 

 to the ground by a thread which they spin. These geometers, or measuring 

 worms, enter life from the egg at the time the leaf is uufolding and develop 

 very rapidly. They eat but little while small, and for this reason their' 

 work is not noticed until they are nearly grown, when they are ravenous 

 feeders. They very soon leave the tree and enter the ground to 

 change to a moth that will lay eggs for the next year's generation. Part 

 of these moths appear late in the fall, and lay their eggs, but the greater 

 share of them wait until the following spring. The female is wingless, 

 and must crawl up the tree to deposit her eggs. Many have taken advan- 

 tage of this peculiarity and placed tarred bands around the trunks, or tin 

 collars, sloping so that she can not crawl over them, and thus prevent egg- 

 laying. Bands of wool, such as are used for climbing cut worms, will prob- 

 ably serve the purpose even better, as they will not mat nor harden with 

 moisture. They should be made tight to the trunks but left loose outside. 



Fig. 10 A.— Canker Worm, a, male moth ; 

 6, female moth. 



Fig. 10 B.— Canker Worm, o, 

 larva, natnral size ; b, eggs, 

 natural size and enlarged. 



Remedy. — The means of prevention just given are very good ones, but 

 if the trees are given a thorough spraying with Paris green at the first 

 notice of the canker worms, there need be little trouble in controling them. 

 By a careful search on the young leaves near the ends of the twigs, the 

 small, slender, dark-brown loopers may be found before the trees blossom. 

 They are then young and have done comparatively little harm. This is 

 the time when spraying is a success. Where so many fail with spraying 

 is in waiting too long before applying the remedy. One may be almost 

 certain of finding the canker worms the second year if they have appeared 

 in an orchard. 



CLIMBING CUT-WORMS. 



In the fruit belt .along the shore of lake Michigan and on sandy soil 

 in other parts of the state, climbing cut-worms are frequently the most 

 dreaded of the orchard pests. They appear early in the spring while the 

 leaf buds are opening, and come in such great numbers that, if one is not 

 prepared to stop their work at once, they denude whole orchards in a few 

 days' time. The cut-worms hide in the ground near the surface during 

 the day, and are found in the trees only at night, when they feed. They 

 37 



