FIFTY-KIRST ANNUAL UEPORT. 101 



word : it will be worth while to remember that while the first generation 

 is usually of fewer numbers than the second, nevertheless the individuals 

 that escape the first spray become the parents of the second generation. 



PEAR PSYLLA. 



The work on pear-psylla this year was carried on in cooperation with 

 Mr. Dutton of the Department of Horticulture. We were able to make 

 use of our inscctary to good advantage in this project in the following 

 way: During the late winter Mr. Dutton very kindly secured a quan- 

 tity of hibernating psyllas in a birds' nest, taken from a pear orchard 

 badly infested. These hibernating forms were brought in while still cold 

 and we placed them in a cage in our insectary, together with a number of 

 pear twigs. The psyllas promptly came out and in due time deposited 

 large numbers of eggs on the twigs, making it possible to carry on tests of 

 different spray solutions right in mid-winter. After testing a number of 

 substances it was finall}^ decided that lime-sulphur was most effective. 

 After this the whole thing hinged on the exact time of application to get 

 the optimum results. Mr. Dutton will discuss this matter at length and 

 give you the results of field trials over which he exercised supervision. 



THE FRUIT TREE LEAF ROLLER. 



The fruit tree leaf roller has for a number of years been getting worse 

 and worse in Michigan and at present it is spreading to new fields. An 

 attempt was made this year to find an efficient spray, in hopes of killing 

 the creature in the egg stage. An orchard 'of Mr. Oscar Braman, near 

 Muir, happened to be badly infested and this was selected for the trials. 

 A visit to the orchard, early in the season, resulted in bringing in many 

 egg masses which were treated as were the eggs of the pear-psylla. Just 

 before the time of hatching they were treated with various sprays, mixed 

 of various strengths and then watched to determine the best material 

 to use. Pratt's scalecide seemed to give us the best results when used 

 strong enough, so this material was decided on for the spray. Mr. 

 Braman then sprayed his orchard using one part of scalecide to twelve 

 and a half of water, just before the time of hatching of the eggs. The 

 spray was applied at the time when the buds burst and with very good 

 success, the number of worms being reduced quite markedly over those 

 found in previous years. These two instances illustrate the use to 

 which an insectary can be put and the advantage obtained in determining 

 the best method of procedure long before the regular time of application 

 occurs. 



CODDLING MOTH. 



An attempt was made to set a time for the second generation of codling- 

 moth as in previous years. Thirteen stations over the State were used 

 for making observations and the time computed for all parts of the 

 State, where apples are grown. We experienced difficulty in several 

 cases because of delay or failure in getting reports from the observers. 

 We hope next year to arrange to get these reports by wire in each case 

 and on the day on which the insects emerge. Another difficulty was 

 caused by people spraying too early, reasoning that it was good to get 

 the spray on good and early. Of course, a spray put on early is inade- 

 quate to protect the fruit until picking time and as the season was such 



