105 



but did not survive to the adult stage. Ormenis pjgmaea, F., and the 

 Jassid, TeUigonia occatoria, are both common but not seriously injurious. 

 A mealy-bug, provisionally identified as Pseudococcus adonidum, L. 

 (longispinus, Targ.) is sometimes abundant in the berry clusters. In 

 the spring the Aphid, Toxoptera aurantii, Boyer, is very abundant on 

 the new shoots, which it may damage severely. The orange, which 

 is frequently allowed to grow half wild among cofiee, is another host- 

 plant of this Aphid. An undetermined Chalcid has been bred from 

 this insect, which is also at times almost completely controlled by the 

 fungus, Acrostalagmus albus. Two species of May beetles that attack 

 coffee are probably new and will be described later. While the larvae 

 attack coffee, they are primarily pests of cane. Two Tachinids have 

 been reared from adults of Lachnosterna (Phyllophaga) ; one, Cnjpto- 

 meigenia aurifacies, Walt., is fairly abundant, the other, Eutrixoides 

 jonesi, Walt., being comparatively rare. 



Safro (V. I.). When does the Cost of Spraying Truck Crops become 

 Prohibitive ? — Jl. Econ. Entom., Concord, N.H., x, no. 6, December 

 1917, pp. 521-523. 



The author discusses the cost of insect control work and points out 

 that while many entomologists, as well as growers, have considered 

 that when the cost of spraying reaches ^^^thin a fraction of the profit 

 expected, it becomes prohibitive, they forget that the investment 

 itself often represents a much larger amount of money than the season's 

 return. When, for example, some £30 to £35 per acre has been 

 expended in growing onions and a severe epidemic of onion thrips 

 [Thrips tabaci] is threatened, it is undoubtedly an economic necessity 

 to spend as much as £10 per acre in spraying to save even £20 of the 

 original investment. The cost of spraying fruit trees in any season, or 

 series of seasons, cannot be worked out as easily on the basis of annual 

 returns as in the case of annual truck crops where the entire business 

 transaction is completed within one year. In the control of j)ests with 

 a wide range of food-plants it is frequently asserted that the effect of 

 spraying a field would only be temporary and that in several days the 

 field would again be infested by insects migrating from neighbouring 

 weeds and cultivated plants. The author does not consider this to be 

 necessarily true. It is found, for example, after spraying bean fields 

 in Florida against Jassids that the insects reappear after a time ; 

 growers have nevertheless found it advisable to spray in order to keep 

 down a sufficient proportion of the insects to allow of plants becoming 

 sufficiently hardy to withstand a severe attack such as would entirely 

 destroy young, untreated ones. 



The author discusses the possibility of formulating a rule that would 

 apply eventually to the spraying of both truck crops and fruit trees, 

 and submits the following suggestion for discussion : " The cost of 

 spraying truck crops for pests that threaten to destroy all or a large 

 part of the crop does not become prohibitive until the immediate 

 apphcation in view, together with such following farm operations as 

 can be definitely foreseen, have a total cost in excess of the reasonable 

 expectations of gross returns from the c op in question." There must 

 of necessity be many applications the reason for which cannot be 

 definitely foreseen, resulting in some cases in the cost of spraying 



(C452) B 



