Effect of Gregarina sp. parasitism on the susceptibility of Blattella germanica to some control agents.

Gregarines are enteric parasites of invertebrates but little is known about the negative effects of this parasitism on host species. The present study evaluates the influence of the parasitism of Gregarina sp. on the survival of Blattella germanica and methods for elimination of gregarine infection in laboratory rearing systems. Insects were dissected and the infection was detected in 80% of a sample of 50 adults. Diseased cockroaches had swollen abdomens, slower movement at high incidences of the protozoan, and short antennas. Dead cockroaches showed darkened body and putrid smell, indicating septicaemia. Infected insects were more susceptible than healthy cockroaches when treated with Metarhizium anisopliae and triflumuron.