A total of 33 strategic release locations were selected by field staff to obtain the greatest
coverage possible in the state. All of the areas selected had a history of Mexican bean beetle
pressure and it was hypothesized that releases in these areas would be the most effective way
to mitigate the Mexican bean beetle population without the nurse plots. The vast majority of
the sites were in the inner coastal plain which is located from Salem and Cumberland
Counties through Monmouth and Middlesex Counties. The adult parasitoid, Pediobius
foveolatus (Hymenoptera: Eulophidae), was released into the sites where female wasps attack
or “oviposit” on all larval instars (1st through 4th) of the Mexican bean beetle. A single female P.
foveolatus deposits an average of 25 eggs within each MBB larva. After 5 to 7 days
parasitized larvae die, forming dark brown "mummies" (Figure 1). An average of 25 wasps
(70% -75% female), successfully develop and emerge from each parasitized MBB larva.
Newly emerged female wasps mate and readily disperse from the release sites to search for
MBB larvae in adjacent soybean fields.
The goal of the program was to release 8,000 parasites, depending on their availability, in
each of the fields. Each field was surveyed once per week throughout the peak Mexican bean
beetle season resulting in six field surveys per site. Very few Mexican bean beetle were
observed and no numerical data were collected due to time and personnel constraints.