CAPE COD CRANBERRY INSECTS 11 



Reflooding before riio.st of tlie eggs liaU-li (say about May '25), if not fol- 

 lowed by a later treatment, tends to make an infestation worse, for it inter- 

 feres witli the progress of spiders and parasites onto the hog. 



Late HoUliiKj of the Winter Flood. 



If the winter flowage is lield late'-* and shallow and the weather is warm, 

 many of the eggs hatch under the water and the worms drown. If held till 

 August, it kills all the eggs tliat are under water and fail to hatch, but it also 

 cuts off the season's crop and' often so injures the vines that it takes them a 

 year or two to recover. 



Any liolding of tlie winter flood after about May 10 generally tends to 

 control this insect by shortening its active season and thus increasing the sup- 

 pression of the second lirood. If it is held till May 25, the chances are nearly 

 even that this brood will be suppressed entirely. Where water supplies are 

 limited, advantage should i)e taken of this more generally than it has been. 

 Probably it is best to hold tlie winter water on most such bogs till May 22 

 rather regularly,^" and also spray as recommended below. Besides helping to 

 control the fireworm such late liolding of the winter flood keeps the vines in 

 condition to resist frost till about June 1, much improves the keeping quality 

 of the fruit, controls the false armyworm and largely checks tlie fruit worm 

 and gypsy moth. 



A good treatment for serious infestations on large bogs is to bunch the 

 hatching of the eggs by liolding the winter fl>od till June 1, and reflood 

 three weeks later. 'I'his generally cleans out the fireworm well, but reduces 

 the season's crop. 



Sprotii-vij. 



The following is a standard sj)ray for tiiis pest on tlie Cape:" 



4-0 per cent nicotine sulfate 1 quart 



Fish-oil soap 4 or 5 pounds 



Water 100 gallons 



It should be used against the first brood from one to four times according 

 to circumstances, and against the second brood once or twice depending on 

 how much the hatching is suppressed. This spray never harms the leaves or 

 blossom buds, but it often blasts the flowers and small berries. If the soap 

 is left out, however, it is safe to use during and after the bloom. It is a bit 

 less effective without soap, but this may be made up for somewhat by adding 

 6 pounds of dry lead arsenate. It must be applied thoroughly and in suf- 

 ficient quantity not only to wet completely the tops of the vines but to pen- 

 etrate the tips webbed by the worms. Three liundred gallons or more to the 

 acre should be used for each application. 



The second brood must be treated as soon as hatching is general, usually 

 five or six days after the first worms appear, for the following reasons: (1) 



9. Till late May or later. 



10. Such late holding is generally advisable only on mature bogs that ere completely flooded 

 with less than 18 inches of water. 



11. Since this bulletin was written, a new spray, sodium oleate-oleoresin of pyrethrum, has 

 been found so effective in controlling the various fireworms and cranberry spanworms and leaf- 

 hoppers that it promises largely to displace nicotine sulfate as a cranberry insecticide. Un- 

 fortunately, this material has not yet been standardized, so the advisability of its use is curtailed 

 somewhat for the present. More extensive experience with it is necessary before an adequate 

 discussion of its use is possible. It should be used in concentrated form with sodium silicate 

 added, apparently at the rate of a pound in about fifteen gallons of water. 



