PLUM CURCULIO IN APPLES 



Table 5. 



Insecticide 



-Average Life of Plum Curculio Beetles Feeding on Poisoned 

 Fruit. Waltham, Mass., 1931 



Average Number of Days Alive 



Lead arsenate 3 lbs. -100 

 Lead arsenate 4 lbs. -100 

 L?ad arsenate 5 lbs. -100 

 Lead arsenate 6 lbs. -100 

 Check 



When concentrated lime-sulfur solution at the rate of 2 gallons in 100 gallons, 

 and chemical hydrated lime at the rate of 10 pounds in 100 gallons, were added 

 to the lead arsenate-fish oil mixture, the beetles lived slightly longer at the two 

 lower temperatures, indicating some repellent action under these conditions. 

 At the higher temperature, however, this mixture appeared more efficient than 

 the lead arsenate alone or with fish oil, which seems to indicate that when a 

 fungicide is needed in a spray especially applied for combating the plum curculio, 

 lime-sulfur and chemical hydrated lime can be added without .seriously reducing 

 the insecticidal value of the mi.xture. A suminary of these records is given in 

 Table 6. 



Table 6. — Average Life of Plum Curculio Beetles Feeding on Fruit Poisoned 

 with Different Sprav Mixtures. Waltham, Mass., 1931 



Average Number of Days Alive 



Iiisec^ticide 



At 55° F. A t 65° F. At 75° F. At 85° F. 



Lead arsenate 4 Ibs.-lOO 10.7 6.5 5.0 3.1 



Lead arsenate 4 Ibs.-lOO 1 ^^^ ^^^ 49 39 



P^ish oil 1 pint J 



Lead arsenate 4 lbs. -100 ] 



Lime-sulfur 2 gallons [ ^2.4 7.0 4.45 2.85 



Chemical hydrated lime 10 lbs. f 



Fish oil 1 pint J 



RELATION OF TEMPERATURE TO THE CONTROL OF THE PLUM 

 CURCULIO IN THE ORCHARD 



Suggestions for Spraying 



In Massachusetts the climate is very variable during May and Juno, fre- 

 quently changing from periods of cold wind and rain to periods of abnormally 

 high temperatures. These climatic irregularities govern the activities of the 

 I)lum curculio and other pests in the orchard in much the same way as shown by 

 this study of their response to artificially maintained temperatures, and place a 

 premium on the timeliness of the application of control measures. Newly ap- 

 plied sprays are more effective during periods of maximum curculio activity than 

 are older spray residues. It would seem that the coating of poison, especially 



