-5 - 
The briefness of the period (about 7 to 10 days each year) during 
which reliable surveys can be conducted prevents extensive studies of 
this nature in any one year. However, the results of the surveys that 
have been made, and the very large numbers of Tiphia adults often 
seen during the flight period, suggest that this parasite may be of much 
greater benefit than is usually thought. 
Where Can Tiphia Wasps Be Used? 
The spring Tiphia is believed to contribute enough to the natural 
control of the Japanese beetle to be worthy of colonization at all points 
in the infested area where it is not present. Although natural controls 
are constantly expanding, their spread generally lags several years 
behind that of the beetle. Colonization accelerates their establishment 
in the newer infested areas. 
It is desirable to provide freshly liberated colony units of Tiphia 
with all possible advantages in order to assure establishment in -the 
new area. Therefore, colony sites that offer favorable habitats of a 
permanent nature, together with adequate grub populations, are chosen, 
as far as possible. Desirable terrain for initial colony establishment 
is represented by golf courses, parks, cemeteries, estates, and 
pastures, when a degree of permanence is assured. In such situations 
not only the type of turf most suitable for the Japanese beetle grubs 
but also shaded foliage, upon which the adult Tiphia wasps find their 
food, are usually present and make possible a thriving colony from 
which the parasites can spread into surrounding areas. 
The practice of selecting such areas for initial colonization may 
have led to the erroneous belief that the parasites are too selective as 
to habitat and will not spread into less suitable agricultural areas. 
Surveys of intervening terrain, made after sufficient time had elapsed 
for the original colonies to have developed volume, show that Tiphia 
wasps are found in varying abundance when such areas are also 
favorable for the grubs. 
A total of 1983 colonies of Tiphia vernalis have been liberated by 
Federal Government through 1949. It has been possible to scout 45 
percent of the colony sites and the parasite has been recovered at 67 
percent of those scouted. Some of the surveys have been made only 
for brief periods and under unfavorable weather conditions. Further 
surveys with better weather would undoubtedly show that the parasites 
are present at more of the sites. 
This parasite has been placed over a wide area extending from New 
Hampshire to Virginia and westward to Ohio. Recoveries have been 
made from the extremes of this distribution, but there has not been 
sufficient opportunity to study the parasite's abundance and adaptability 
in the northern areas. 
