191o.] PUBLIC DOCUMENT — No. 31. 231 



bogs which cannot be reflowod in June after having been winter- 

 flowed, is not after an infcstaiion has fully developed and so 

 threatens vines and crop that something must he done at once, 

 hid is he fore tJie infestation starts. Cutting oil" the stragglers 

 by spraying at the proper time every year, whether the insect 

 appears to be present or not, will greatly retard the development 

 of an infestation, if it does not completely stop it. Spraying 

 for the stragglers need not be as effective as it wonld have to be 

 under conditions of bad infestation, because the natural ene- 

 mies of the fireworm will take care of most, if not all, of the 

 worms which escape the poison. Unless the work of spraying 

 for a heavy infestation is extraordinarily thorough and effective, 

 there will be left, at best, a far greater number of unharmed 

 worms than their natural enemies can begin to cope with. 



Some will probably object to this method of treatment on the 

 ground of expense. This, however, does not seem to be a valid 

 objection v.-hen we consider that the prevention of the loss of a 

 single average croj) will make up for the expense of four good 

 sprayings each year for a period of ten years. Then, too, as our 

 spraying experiments, discussed in this report, have shown, 

 most bogs should probably be sprayed several times each year to 

 control fungous diseases. The fireworm spraying may be done 

 at the same time, by using an excess of lime in making the Bor- 

 deaux mixture and adding a pound of Paris green to every 50 

 gallons, at an additional annual expense of perhaps $3.50 per 

 acre. 



While the prevention of infestation by this insect is impor- 

 tant, it is necessary to consider how a fully developed infesta- 

 tion may be most easily cleaned out. As indicated in last year's 

 report, the most serious obstacle usually encountered in ridding 

 a bog of a bad infestation is the length of the hatching period, 

 especially of the eggs that produce the first brood. This period 

 seems to be much prolonged on bogs with thick vines, probably 

 because the vines so shade the eggs on the lower leaves that 

 their development is much slower than that of the eggs which, 

 placed on the tops of the vines, are more exposed to the sun. 

 In extreme cases, which are not uncommon, the hatching period 

 is so much prolonged that there seems to be no time during the 

 vear when ecgs of either the first or the second brood are not 



