ABSTRACT
Oligonychus ilicis (McGregor) (Acari: Tetranychidae), commonly known as the southern red mite, or as the coffee red spider mite in Brazil, is one of the main species of herbivorous mites that causes serious damage to coffee plants (Coffea spp.) and thus negatively affects coffee production. Among the biocontrol agents, predatory mites of the family Phytoseiidae play an important role in many biological control programs worldwide due to their potential as suppressor of mite populations mainly from the family Tetranychidae. One of the phytoseiid mites usually associated with O. ilicis is Euseius concordis (Chant), which often occurs abundantly in the coffee crops of Minas Gerais State, Brazil. This study was conducted to assess the predation potential of E. concordis feeding on the larvae and nymph stages of O. ilicis on coffee plants (Coffea arabica L.). Logistic regression analysis revealed a Holling type II functional response, showing that the number of O. ilicis killed by E. concordis increased gradually as the density of O. ilicis increased. Average daily oviposition also increased with prey densities above 6.3 mites/cm2, indicating that maximum oviposition rate is about 1 egg/day. Results of this study suggest that E. concordis has the potential to reduce O. ilicis populations, and this predatory mite can therefore be considered an important natural enemy of the pest O. ilicis in coffee plantations.
Subject(s)
Coffea/parasitology , Mites/physiology , Pest Control, Biological , Tetranychidae , Animals , Brazil , Female , Oviposition , Predatory BehaviorABSTRACT
A minute pirate bug, Amphiareus constrictus (Stål) (Hemiptera: Anthocoridae), the biology of which has been less studied, was successfully reared in the laboratory for more than 20 generations. Studies were conducted to understand its biology, life table parameters, and predatory potential. Besides the adult, the egg and all five nymphal instars are described with live images, which can serve as additional characters for identification. The biological parameters were studied at different temperatures. Rearing temperatures of 25 and 30°C were found to be suitable for hatching and nymphal survival to adult stage (88.5 and 75%, respectively). Life table parameters like net reproductive rate (R0), precise intrinsic rate of increase (rm), finite rate of increase (λ) and hypothetical F2 females were higher at 25°C. A nymph could consume a total of 32.8 ± 1.8 Corcyra cephalonica Stainton eggs. Male and female adult consumed a total of 179.0 ± 15.6 and 388.5 ± 58.6 C. cephalonica eggs, respectively. The data generated through studies on biology, fertility, and predatory potential led to the standardization of a simple production protocol for A. constrictus utilizing the eggs of the rice moth C. cephalonica. Predatory potential studies on Tuta absoluta (Meyrick) indicated that a nymph could consume 154.8 eggs during nymphal duration. Male and female adults could consume 1280.5 and 1435 eggs, respectively. The mass-reared A. constrictus can be field evaluated against the tomato pinworm TT absoluta and the brown plant hopper Nilaparvata lugens Stål.