Abstract

VECCO, Daniel; PINEDO, Román  and  FERNANDEZ ARGUDIN, Miriam. Sampling methods for monitoring of Pseudophilothrips sp. (Tubulifera: Phlaeothripidae) and its natural enemies:: II. Binomial sequential sampling of Eurotas brasilianus Carvalho and Wallerstein (Miridae: Orthotylinae) and Macrotracheliella sp. (Anthocoridae: Anthocorinae). Rev. Protección Veg. [online]. 2015, vol.30, n.2, pp. 81-86. ISSN 2224-4697.

The present paper is the second of two approaching the determination of sequential sampling methods: (1) enumerative and (2) binomial, for monitoring of Pseudophilothrips sp. and its natural enemies in the agroecological system of Plukenetia volubilis L. in San Martin, Peru. During 2007-2009, a total of 202 population samplings were carried out in an agroecological plot of P.volubilis. Ten leaves per each of the three plant thirds, ten inflorescences and ten fruits were taken. Based on the significant values of the coefficients a (intercept) and b (aggregation) of Taylor`s Power Law, a card was made relating the sampling size with the plant frequencies p and the mean m, whose relation was adjusted by comparing three functions: Kono and Sugino`s empirical manner, (b) Wilson and Room`s function, and (c) Poisson`s distribution. A cutting value T=0 was considered, and the sampling size was estimated. The referential parameters of the sampling card were adjusted by n + 0.5 and rounded to whole numbers. Simulations compared with the records for n=25 were carried out. The frequencies of plants with natural enemies (p) fitted the negative binomial distribution (BN) (k=1.62; R²=94%). The function of p and m was better adjusted to Wilson and Room's manner (R²= 93.20). With the card made for a maximum of 30 plants, the mean was successfully estimated for the error margin E_50%, for values between 0.20 and 0.92 individuals/plant, in 92% of the simulations. Sampling required 13 ± 8 plants (48 ± 32% vs. 40 ± 24% of the enumerative sampling). In 22.7% of cases, the simulation exhausted the number of plants without reaching the required value for p, but it offered. appropriate mean estimations.

Keywords : sacha inchik; inka peanut; thrips; biological control; presence-absence sampling.

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