ISSN: 1659-2751

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Evaluation of the Nematicidal Effect of Pineapple Leaves on the Biometric Parameters of the Banana Plants and on Soil Macrofauna

Abstract

The pineapple crop represents a large environmental problem in Costa Rica because of the high volumes of foliage it produces. Poor management of this waste increases the presence of the stable fly (Stomoxys calcitrans). Experiments were carried out in vitro, in a greenhouse and in the field to evaluate the nematicidal effect of pineapple leaves on Radopholus similis populations, on the biometric parameters of the banana plants, and on soil macrofauna in banana plantations. The effect of four pineapple leaf extracts (two aqueous and two in ethanol), both from organic and conventional plants, were evaluated to determine the mortality of R. símilis, 24 h and 48 h after the treatments were applied. The results showed significant differences (p<0.01) in the evaluated variable. The extract of conventional pineapple showed a higher percentage of mortality (31 %), possibly due to the presence of agro-chemical residues on the pineapple leaves. In the greenhouse pineapple mulch from conventional and organic crops as well as EM-compost were applied to bagged or potted banana plants whose soil had been previously inoculated with 1200 R. similis nematodes each to evaluate their nematicidal effects. The results indicated that the population of R. similis was not reduced in the control group. Results in the field effect showed that pineapple and EM-compost mulch applied to the banana plants increased their biometric parameters with significant differences when compared to the control group, but there was no difference between the treatments. Even though the results are preliminary, they suggest that pineapple stubble can be used as a source of organic matter to increase the development of banana plants. The macrofauna study indicated the presence of 12 arthropod groups used as indicators of soil quality were identified, the predominant groups being: Collembola, Acari, Diptera, Hymenoptera, Coleoptera, of which the Oligochaeta and Dermaptera populations were most abundant. In addition, the absence of the larvae of the Muscidae suggests that the mulch does not represent a breeding ground for Musca domestica or for Stomoxys calcitrans.

Key words: arthropods, banana, extracts, pineapple stubble, nematicides, Radopholus símilis.

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