Spatial and temporal population interactions between the parasitoids Cotesia flavipes and Tachinidae flies: considerations on the adverse effects of biological control practice

Abstract

Biological control of Diatraea saccharalis is regarded as one of the best examples of successful classical biological control in Brazil. Since the introduction of the exotic parasitoid Cotesia flavipes, the decrease of D. saccharalis infestation in sugarcane fields has been attributed to the effectiveness of this agent. Recently, the native tachinid fly parasitoids (Lydella minense and Paratheresia claripalpis) have also been implicated in the success. Here, we investigated the spatial and temporal population interactions between C. flavipes and the tachinid flies, and provide a critical analysis of the biological control practice, focusing on the undesirable effects of introductions of exotic natural enemies. To investigate these questions, a large data set comprising information from two sugarcane mills located in the state of Sa˜o Paulo, Brazil (Barra and Sa˜o Joa˜o Mills), was analysed. Analysis of the correlation between C. flavipes and tachinid fly population densities through time revealed that such populations were inversely correlated in the Sa˜o Joa˜o Mill and not correlated in the Barra Mill. Logistic regressions were computed to investigate the proportion of sites occupied by the parasitoid species at both mills as a function of time. An increasing trend in the proportion of sites occupied by C. flavipes was observed, with a concomitant decrease of the sites occupied by tachinid flies. This effect was more intense in the Sa˜o Joa˜o Mill. Thus, there is a convincing possibility that constant releases of C. flavipes decreased the tachinid fly populations, resulting in an undesirable effect of biological control practice.

(11Z)‐hexadec‐11‐enal enhances the attractiveness of Diatraea saccharalis main pheromone component in wind tunnel experiments

“…At present, D. saccharalis is controlled either by introduction of transgenic cultivars of sugarcane ( Arencibia et al., 1997; Setamou et al., 2002) or by biological control by artificially introduced exotic parasitoid Cotesia flavipes ( Baker et al., 1992). Both methods have undesirable side‐effects on non‐target organisms ( Setamou et al., 2002; Rossi , 2004; Rossi and Fowler , 2004a,b). Implementation of efficient pheromone‐based monitoring system for D. saccharalis might help to minimize the harm.…”

Efficacy of Cotesia flavipes (Hymenoptera: Braconidae) in Reducing Diatraea tabernella (Lepidoptera: Crambidae) Injury in Sugar Cane

“…in the study area; however, there is no evidence that releases of C. flavipes triggered a decrease in the activity of these tachinid flies during the study period. Although the work carried out by Weir and Sagarzazu (1998) showed that flies were more effective than wasps in inoculations on D. saccharalis larvae in the laboratory, Rossi and Fowler (2004) observed a marked tendency for populations of the tachinid flies L. minense and B. claripalpis to decrease at sites in Brazil where C. flavipes had been released. However, these studies in the Cauca River Valley are, to the best of our knowledge, the first in Colombia, and additional studies should be conducted on future releases of C. flavipes in relation to population densities of L. minense.…”

Biological Control as Part of the Soybean Integrated Pest Management (IPM): Potential and Challenges

“…Despite being less harmful than chemicals, even biological control products should be used with caution. For instance, the massive release of Cotesia flavipes (Cameron, 1891) (Hymenoptera: Braconidae) in sugarcane to control Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Pyralidae) as part of an ABC program carried out for years in Brazil probably displaced tachinid parasitoid flies from the environment where they used to be commonly found [74]. Such undesirable consequences can also happen in soybeans if a biocontrol agent of stink bug is released or applied abundantly in the fields without adopting a sound ET, especially considering the large area cultivated with this crop (around 45 million hectares in Brazil alone).…”