58 NEW YORK STATE MUSEUM 
unopened buds, and consequently spraying to be effective must be 
early enough to catch the insects before there has been much damage 
to either buds or leaves. 
Pear psylla (Psylla pyricola Forst.). There have been 
comparatively few reports of serious injury by pear psylla during the 
past summer. The extremely severe weather of last winter following 
injury by this insect and in some cases reduced vitality due to other 
causes, has resulted in a great deal of winter injury. This has been 
particularly marked in a number of pear orchards which have been 
making an unsatisfactory growth for several years past and have 
undoubtedly suffered to a greater or less extent from pear psylla. 
Trees in these orchards went into the winter in poor condition and 
were unable to survive the extreme conditions. Small limbs and in 
exceptional cases large limbs and in a few instances even most of 
the trunk was practically killed or so badly injured that the trees 
were unable to recover and slowly died back during the spring and 
early summer. Kieffer, Bartlett and Seckle trees fared the worst, 
while Clapps favorite largely escaped damage. 
The pear psylla, it should be understood, is only one of a number 
of contributing causes which weakened the trees in earlier seasons 
so that they were unable to winter successfully. The severe weather 
has emphasized this injury and fruit growers are coming to realize 
as never before the need of keeping the trees vigorous if they are to 
avoid serious damage. 
GARDEN INSECTS 
White grubs (Phyllophaga fusca Frohl.). The year for 
serious white grub injury in Albany, Columbia and Rensselaer 
counties, as well as some other portions of the State, passed with 
little damage compared to the losses inflicted in 1915 and ro12. 
There were some reports of local injury here and there but the affected 
areas were by no means large and the injury could not be classed 
as Severe. . 
It was hardly to be expected that these pests would be able to 
continue in large numbers through a long series of years, though it 
was not anticipated that there would be such a material diminution 
of the insects. This favorable outcome is very probably due in 
large measure to the activities of natural agents, such for example 
as the predacious maggots of the robber fly, Promachus 
fitchi O.S., a species comparatively abundant in infested fields 
in 1913 and 1916. Other natural enemies rendered material service 
in destroying the grubs and even the adult beetles, though the proba- 
