Figure 2. --Tiphia larva 
attached to Japanese 
beetle grub. 
Figure 3. -- Tiphia larva 
almost fully grown. 
How Much Good Does the Spring Tiphia Do? 
The spring Tiphia is one of several natural factors that play a part 
in the control of the Japanese beetle. Each Tiphia, either male or 
female, develops at the expense of a Japanese beetle grub. An exact 
measure of the good done by the spring Tiphia is difficult, because of its 
hidden, underground activities. Surveys have been made in areas 
where the spring Tiphia has been established long enough to give some 
idea of its value in lessening the Japanese beetle population. These 
surveys consist of digging and sifting the soil in a given number of 
square feet, to collect all stages of beetle and parasite that are present. 
To give a true idea of the effectiveness of the parasite the survey 
must be made between the time the adult Tiphia wasps complete their 
egg laying and the time the Japanese beetle appears above ground. 
Between the years 1935 and 1949 thirteen such surveys were made. 
The localities included in the surveys, the type of area sampled, the 
number of samples per area, and the results obtained are shown in 
table 1. 
The Rushland surveys were made when grubs were abundant in a 
small pasture. The colony in this pasture was started with 356 female 
Tiphia parasites 4 years before the first survey. These surveys showed 
a normal fluctation in numbers of parasites. 
