EXPERIMENT STATION BULLETINS. 



191 



FIGHTING THE PLl^M CURCULIO. 



By A. J. Cook, Bulletin No. 66, Zoological Department. 



The Entomologist of the station is very glad to receive specimens of 

 msects, and will always answer inquiries regarding the same. Insects 

 should he sent hy mail in close strong boxes— tin or wood. Paste-board 

 boxes are not strong enough, and are often crushed. Insects sent in letters 

 ■are almost alivays crushed beyond identification unless inclosed in quills 

 or capsules. The postage will not be more than one or two cents. A little 

 ■cotton ivith the insect will prevent jarring and breakage. In case larvcB, 

 oaterpillars, grubs, etc., are sent, some of their food-plants should take the 

 place of the cotton. This prevents shaking and supplies food. No holes 

 should be made to supply air. . Any information regarding the insects 

 sent, will be gratefidly received, and may prove very valuable. Where 

 found; damage done; and any other facis. — A. J. Cook. 



This paper was read in sabstance before the Association for the Promotion of Agricultural Science, 

 at the Indianapolis meeting, August 19, 1890, and at the request of many fruitgrowers is sent out as a 

 bulletin. 



The natural history of the Plum Curculio 

 (Fig.) is well known. The little weevil is 

 hardly more than two tenths of an inch long. 

 It is rough, with elevated longitudinal lines, 

 two of which, on the middle of the back, one 

 on each side, are very prominent. The color 

 is brown, dotted or lined with white and 

 beaded with black. The two large humps are 

 black, and rest on a black quadrangular spot. 

 The beak is about the length of the head and 

 prothorax and is bent under and back. The legs 

 are brown, specked and ringed with white. The 

 femur or main joint of the legs is much thick- 

 ened. The curculio commences to visit the 

 trees late in May in Central Michigan, or at just the time the little dried 

 up circle — the calix — is falling from the young fruit. By jarring the trees 

 I have shown repeatedly that the curculio does not visit them at an earlier 

 date. The insect now commences to feed on the leaves, on the fruit, and 

 the female to lay her eggs. These latter (Fig.) are always laid within a 

 crescent, cut by the curculio, in the fruit. At the base of a little puncture 

 within this crescent, the egg is ea.sily found. The insects continue to lay 

 eggs till the first of July, by which time the beetles from the first laid 

 eggs begin to come forth. So that there is no time in the year when the 

 beetles may not be found. During June, at time of egg-laying, the beetles 

 often spend the day, especially early in June, when the weather is cold, 

 concealed under clods or chips, beneath the tree. Towards night-fall they 

 seek the fruit and may walk up the trunk of the tree, or may fly from the 

 ground to the tree. I have seen them going both ways. 



a larva ; h pupa ; c imago ; d stung 

 plum. 



