Banca de DEFESA: ROSINEIDE DOS SANTOS COSTA

Resistance of banana cultivars Musa spp. (Zingiberales: Musaceae) to the mite Raoiella indica Hirst (Acari: Tenuipalpidae)

Red palm mite; Musaceae; Pest mites; Varietal control

The mite Raoiella indica Hirst, 1924 (Acari: Tenuipalpidae) was originally reported in Brazil in 2009 causing negative impacts on several plant species, among the most important are the families Arecaceae and Musaceae. In Brazil, there are few studies investigating banana tree varieties resistant to the red palm mite. Thus, the present study aims to test six banana cultivars to determine the survival of R. indica and to verify the possible resistance of the cultivars to this mite. At the Laboratory of Entomology and Acarology /LEA at UFAL, Campus Arapiraca, leaf discs of six banana cultivars ('Grand Naine', 'Maçã', 'Prata Anã', 'Prata Catarina' 'Prata Gorutuba' and 'Thap Maeo') (Musa sp.) and coconut Cocos nucifera L. (Arecaceae) (control) were infested with five couples of R. indica and kept in B.O.D, at 25 ± 2 ºC, 57% ± 5 RH and 12h photophase. The evaluations took place daily with verification of the number of live mites and deposited eggs, number of larvae, nymphs and emerged adults. With these data it was possible to calculate the average survival of adults and of females and males separately, in addition to egg viability and survival of immature forms. The design was completely randomized with seven treatments (six banana cultivars + coconut as control) and 10 replications. The results were subjected to analysis of variance and their means compared by the Scott-Knott test using the statistical program AgroEstat ver. 1.1. The maximum longevity of R. indica was observed in the coconut tree at 44 days and at 41 days in the banana cultivar 'Prata Catarina'. The lowest maximum longevity rates were observed in 'Grand Naine' (26 days) and 'Prata Anã' (33 days). Regarding the sex of the mite, regardless of the evaluated cultivar, the females had greater longevity and survived until the 44th day of evaluation. Total oviposition was higher in the control (13.16 eggs) and in 'Thap Maeo' (1.86 eggs), but the latter did not differ from 'Maçã' (1.74%). The lowest oviposition averages occurred in 'Prata Anã' (0.43%) and 'Grand Naine' (0.05%), differing between themselves and between the other banana cultivars and the control. The oviposition period ranged from 21.9 days in the coconut tree to 2.1 days in the 'Grand Naine' cultivar. Considering the viability of the entire development period (egg-larvae-nymph-adult) of R. indica, there was a significant difference between the coconut palm and among all banana cultivars. The survival of the R. indica mite was higher in the 'Prata Catarina' cultivar and in the 'Thap Maeo' cultivar there was the longest oviposition period and the highest average number of eggs. In the 'Grand 'Naine' and 'Maçã' cultivars, the immature forms did not reach the adult stage. The 'Grand Naine' cultivar can be considered resistant to R. indica attack.