Dactylopius opuntiae (Cockerell) (HEMIPTERA: DACTYLOPIIDAE) POPULATION FLUCTUATIONS AND PREDATORS IN TLALNEPANTLA, MORELOS, MEXICO

Resumen

The cochineal scale insect, Dactylopius opuntiae (Cockerell), is a key pest of Opuntia spp. (Plantae: Cactaceae). It reduces the plants’ useful-life and affects production of their cladodes and fruit. Chemical control is the main strategy, but it is inefficient and a risk for environment and human health. For this reason, other management strategies are required, for example biological control with entomophagous insects. To this end, the population dynamics of D. opuntiae and its predators were studied in three commercial plantations of Opuntia ficus-indica (L.) Miller cactus grown for production of tender cladodes in Tlalnepantla, Morelos. The study was conducted from February to August 2008. Weekly random samples were taken of adult females from 50 colonies in each plantation. Abiotic factors recorded in the three sites were precipitation, temperature and relative humidity. Pearson correlation indexes were determined for the pest, its predators and the abiotic factors. The entomophagous insects Leucopis bellula (Diptera: Chamaemyiidae) and Sympherobius barberi (Neuroptera: Hemerobiidae) were the most correlated with D. opuntiae, r = 0.3931, p = 0.0005 and r = 0.3075, p = 0.0073, respectively. Relative humidity (r = -0.5648, p < 0.0001) and number of days with observable precipitation (r = -0.5621, p = 0.0189) negatively affected D. opuntiae abundance, while mean temperature favored population growth (r = 0.3899, p = 0.0039).