INJURIOUS INSECTS OF 1904. 83 



CONTROL OF MELON BLIGHT AND LEAF-EATING 

 MELON INSECTS. 



That this troublesome fungus disease, which works on melons and 

 cucumbers, can be combated, if treatment is begun early enough, has 

 been practically demonstrated. Bordeaux mixture properly made and 

 properly applied has been found successful. It must be borne in 

 mind, however, that any application affects only the surface, and the 

 surface must be kept coated, thus preventing the spores from germi- 

 nating and starting a growth in the tissues of the leaf, for then it 

 cannot be reached. Applications of Bordeaux mixture should be 

 begun as soon as first leaves of plant appear, and should be repeated 

 every eight or ten days for six or seven weeks. Fewer sprayings might 

 possibly do, but it is better to err by giving too many, than to run the 

 risk of the fungus getting a foothold by giving too few. The melon 

 raiser must begin spraying early, as above indicated ; if he delays, 

 his ivork and material are zvasted. A Knapsack sprayer might be 

 profitably used for the first few applications, but after the vines are 

 larger, and call for more liquid, a spray pump and barrel are desirable. 

 Further, the grower must distinguish between this blight and the wilt 

 caused by a bacterial organism, since the Bordeaux does not afTect 

 the latter. Plants showing this wilt should be destroyed at once. 



What is known as the 4.4.40 sol. of Bordeaux is used for this 

 work, and it is made as follows : Dissolve four pounds of copper 

 sulphate (blue vitriol) in four gallons of water in a tub or crock ; 

 slake four pounds of good quick lime slowly, adding water as it slakes 

 to make four gallons. When wanted for use, and it should be used 

 very shortly after it is made and not kept for some time, add sixteen 

 gallons of water to each mixture, lime and blue vitriol, and then pour 

 the two solutions together. Do not mix the solutions before diluting. 



It is eminently essential that the Bordeaux mixture be not acid, in 

 order that it may not burn the foliage. There are various tests to 

 determine whether it is or is not acid : 



1. If a clean knife blade held in the solution a minute or two 

 becomes copper coated, more lime should be used. 



2. If a little of the solution be poured into a shallow dish, and 

 one gently blows across its surface, a thin film should form ; if it does 

 not, add more lime. 



