Controle alternativo de Tetranychus urticae com extratos de sementes de graviola, Annona muricata L. e com ácaro predador Amblyseius aerialis (Muma, 1955) (Acari: Phytoseiidae)

Abstract

Because of the importance to control the spider mite, Tetranychus urticae (Koch, 1836) (Acari: Tetranychidae), studies with alternative methods to use of chemical acaricides, has been needed. The aim to the present study was to evaluate the effect of seed extracts of Annona muricata L. (Annonaceae), on mortality, repellency, egg viability and persistence in controlling of T. urticae. As, evaluate the potential of predatory mite Amblyseius aerialis (Muma, 1955) (Acari: Phytoseiidae) through studies of functional and numerical response. The ethanolic extract showed greater toxicity to the T. urticae, with LC50 estimated at 0.2% (v/v), followed by hexanic and aqueous extracts, with LC50 estimated at 0.4% (v/v) and 13.0% (m/v), respectively.The reason for the toxicity LC50 of the ethanolic extract was 2.0 and 65.0 in relation to the hexanic and aqueous extracts, respectively. The acaricide Abamectin Nortox®caused 40.0% of mortality. The concentrations 0.07, 0.1, 0.2% (v/v) and the acaricide had a neutral effect on T. urticae and the concentrations 0.4, 0.6 and 1.4% (v/v) have been repellents. Egg viability for the ethanolic extract (LC99), acaricide and control was 9.5; 76.5 and 91.5%, respectively. The ethanolic extract showed persistence until 120 hours after application, with a mortality rate above 80.0% and chemical control had persistent until 48 hours after application with a mortality of 47.3%. To evaluate the functional and numerical response, eggs, nymphs and adults of the T. urticae were used as prey for the mite A. aerialis, being offered in densities: 2, 5, 10, 15, 20 and 30 mites/arena. The mite A. aerialis has consumed greater number of eggs (81.1%), followed by nymph (49.9%) and adult (26.6%) of T. urticae. There was an increase in the amount of prey consumed with the increased amount of prey offered. Predation of adult of T. urticae by A. aerialis was 0.87 and 1.85 mites/day at densities 2 and 5, respectively, occurring higher consumption in densities 10, 20 and 30 with a mean of 3.23, 2.28 and 2.89 mites/day, respectively. When nymphs offered in densities 2, 5, 10 and 15 mites/arena, the predation was 1.53, 4.19, 4.36 and 3.80 mites/day, respectively, and the densities 20 and 30 predation was 6.0 and 6.6 mites/day, respectively. The mite A. aerialis has consumed on average 1.91 and 4.43 eggs/day in densities 2 and 5 eggs/arena and the densities 10, 15, 20 and 30 eggs/arena, was no increase in predation, with 8.98, 10.84, 13.60 and 14.83 eggs/day, respectively. The oviposition of mite A. aerialis remained around one egg/day, with the exception of the experiment in which eggs were offered as prey, the amount of eggs laid was on average 0.23 egg/day. Thus, the use of seed ethanolic extract of soursop is a promising alternative to control of T. urticae, since, has potential in mortality and cause repelling effect, ovicidal and persistence. The control the T. urticae using the predatory mite A. aerialis was efficient, with increased amount of mites preyed with increasing amounts of preys offered.