THE PECAN LEAF CASE-BEARER,. 



19 



Table XIV. — Spraying experiments against the larvae of the pecan leaf case-bearer at 



Monticello, Fla., in 1918. 



Plat No. 



Number 

 of trees. 



Treatment. 



Date of 

 application. 



Results. 



VI 

 VII 



55 

 14 



Paste lead arsenate at 3 

 pounds plus Bordeaux 

 mixture 4-5-50. 1 



Check; unsprayed 



Apr. 18,1913 



Not controlled satisfactorily. About 

 50 per cent of the larvae were de- 

 stroyed, but the buds were badly 

 injured. 



Most buds were infested by larvae. 

 Some trees were nearly defoliated. 









1 Bordeaux mixture was used for fungicidal purposes. 



Table XV. — Spraying experiments against the overwintering larvae of the pecan leaf 

 . case-bearer at Monticello, Fla., in 1914- 



Plat No. 



Number 

 of trees. 



Treatment. 



Date of 

 application. 



Results. 



IV 



V 



VI 



10 

 10 

 25 



Commercial lime-sulphur 

 solution at 1 gallon to 40 

 gallons of water. 



40 per cent nicotine sul- 

 phate at 1 part to 700 

 parts of water. 



Paste lead arsenate at 3 

 pounds to 50 gallons of 

 water (2 applications). 



Apr. 2, 1914 



do 



Apr. 2 and 10, 

 1914. 



Not controlled. Some few larvae killed, 

 but the majority continued to feed 

 upon the buds and foliage. 



Not controlled. Much damage done 

 to the buds and foliage. 



Not satisfactorily controlled. Many 

 larvae killed, but sufficient numbers 

 escaped to inflict serious injury to 

 buds and foliage. 



As shown in Table XIV, a single application of paste arsenate of 

 lead at 3 pounds to 50 gallons of Bordeaux mixture, made on 

 April 18, 1913, failed to control the pest, although there was 

 considerable benefit in favor of the sprayed over the check trees. 

 Table XV shows that on trees treated with commercial lime-sulphur 

 solution at 1 : 40 and 40 per cent nicotine sulphate at 1 : 700 on 

 April 2, 1914, at which time the larvse were emerging from their 

 hibernacula, little or no benefit was derived from the treatment. 

 Compared with the checks, the trees in Plat VI, which received two 

 heavy applications of paste lead arsenate at 3:50 on April 2 and 10, 

 showed that there was much in favor of the treatment, but sufficient 

 numbers of the larvae escaped the poison to do serious damage to 

 the buds and foliage. 



On account of the manner in which the larvae feed upon the buds, 

 it was found to be difficult to kill a large proportion of them before 

 considerable damage had been done to the foliage. Results show 

 that spraying with lead arsenate during the spring can not be relied 

 upon as an effective remedy for this pest. 



spraying experiments against larvae in the summer. 



Experiments at Monticello, Fla. 



After discovering the manner in which the larvae attack the foliage 

 during the summer, spraying experiments were conducted to find 

 out if the case-bearer could not be controlled practically at this 

 stage of its fife cycle. The results of this line of work are embodied 

 in the following tables. Table XVI shows the effect of the treatment 

 of 113 ten-year-old pecan trees in the orchard of the Summit Nurseries. 



