50 



sprays is unnecessary in the control of tlie apple maggot, and it is pos- 

 sible that good results may be obtained by spraying walnuts without 

 the addition of the molasses. 



Insects That Injure the Twigs 

 The Pecan Twig Girdler 

 (Oncideres cingulatus Say.) 

 Probably the most commonly noticed injury to pecan trees is that 

 caused by the girdling of twigs. This -girdling is accomplished by 

 the female of the pecan twig girdler. Ordinarily, the insect begins to 

 girdle a suitable twig and then lays about eight eggs beneath the twig 

 or leaf axils. After the eggs have been deposited the beetle returns 

 to the work of girdling the twig and continues until the twig falls of 

 its weight or the wind snaps off the twig which is almost completely 

 girdled. The larval and pupal stages are passed within the twig. Ap- 

 parently moisture is necessary for the development of the insects as 

 eggs on twigs remaining hanging in the tree do not develop. The 

 larvae excavate the entire interior of the twig and pupate in late 

 August, the adults emerging in September. 



Since the twigs lie on the ground all winter it is easy to collect 

 and burn them. However, it must be borne in mind that this insect 

 also feeds on hickory, persimmon, linden and a number of other forest 

 trees so that reinfestation is likely to occur from such sources. Inves- 

 tigations in Texas indicate that a considerable degree of control can 

 be secured by a thorough spraying with arsenate of lead. 



Schedule of Control Operations for Nut Plantings 

 Treatment Date 



Insects to be con- 

 trolled 

 Pecan Shoot Borer 

 Pecan Bud Moth 

 Walnut Caterpillar 

 Fall Web-Worm 

 Walnut Husk Maggot 



Twig Girdler 

 Nut Weevils 



Arsenate of lead 1st application about April 

 IVz lbs. to 50 gals, of 1st or when buds begin to un- 

 water. fold. 



2nd application July 15th. 

 3d application, second week 

 in August. 



Collect and burn 

 fallen twigs. 



In late fall or winter. 



Fumigate with 1 Immediately after harvest. 

 oz. carbon bisul- Practice these treatments 

 phide per bushel of from the beginning of fruit- 

 nuts. Destroy worth- ing to prevent any accumu- 

 less nuts. lation of weevils. 



