Regresar

Intra-Plant Distribution and Population Fluctuation of Raoiella indica Hirst (Acari: Tenuipalpidae) on Coconuts in the State of Falcón, Venezuela

Abstract:

Knowledge of the ecology of the red palm mite, Raoiella indica Hirst, is still fragmentary in South America since it was only recently introduced from East Asia. Gathering intra-plant distribution and population fluctuation data could contribute to developing more efficient sampling methods for R. indica. Taking this into consideration, studies were carried out to determine spatial temporal distribution of R. indica in three commercial plantations in the state of Falcón, in Venezuela. Higher mite numbers were registered on middle and lower leaf portions collected from middle or lower plant strata, suggesting that sampling should be allocated to these canopy areas on coconut trees. The R. indica population showed to be negatively associated with rainfall. In 2010, population levels of R. indica were higher than in 2011 (maximum 7 mites/cm2); this was probably a function of lower rainfall values for that year. In 2011, the highest population levels were reached between April and July, coinciding with the lowest rainfall values over that year. Relating to this population spike, the Amblyseius largoensis population showed a numerical response in relation to R. indica density; this predator species does not appear to be exerting bio-control on the mite pest population.