Why control Processionary Caterpillars?

Processionary caterpillars are an important cause of placentitis in Australia. Since the identification of the role of these caterpillars in placentitis and abortion many stud farms have adopted stringent control strategies which has reduced the number of cases of EAFL placentitis dramatically. One farm has had no cases during the past 6 years whereas in previous years they had 1-2 cases each year.

During 2011 and 2012 the last major outbreak of EAFL occurred in the Hunter Valley. One farm lost nearly 20% of their pregnacies to EAFL placentitis in 2011. Seven farms worked with Dr Myron Zaluski, an entomologist (caterpillar expert) and Dr Nigel Perkins, an epidemiologist, to identify how to identify and control the caterpillars.

Three farms (Intervention farms (blue)) initiated control programs that involved identification and removal of nests, and removal of pregnant mares from paddocks where nest material was found or the host tree species for O lunifer were present. The other 4 farms (No Intervention farms (red) ) did not change management protocols for pregnant mares.

The farms that controlled the caterpillars reduced the number losses due to EAFL placentitis whereas the farms with no control, actually saw an increase in the number of cases of EAFL placentitis the following year.

Controlling the number of processionary caterpillars on a horse breeding farm can significantly improve the number of healthy foals born each year.

Here is the link to the scientific paper:

https://www.sciencedirect.com/science/article/abs/pii/S0737080613007880