Presence/absence sequential plans for pest management decision-making, for arthropods of wet rice ecosystem in Malaysia
1997
M. M. Rashid | S. T. S. Hassan
Presence-absence sequential sampling plans are presented for 11arthropod categories to assist in management of their populationsin the multipest-infested rice crop in Malaysia. Data from visualinspection of 204 samples,with 40 and 100 hills per sample, were used to develop the plans. Action threshold for each of the 11 (5 pests, 6 predators) arthropod categories was obtained through a fourth-order polynomial regression of proportion of infestationagainst mean population densities, at the point of saturation ofinfestation. The pest species are: Nephotettix spp., Nilaparvata lugens, Recilia dorsalis, Sogatella furcifera and Cnapholocrocis medinalis (Pyralidae) and the predators: Cyrtorhinus lividipennis, Anatrichus pygmaeus (Diptera), spiders, Odonata, Paederus fuscipes and Casnoidea spp. Risk levels of Type I (alpha) and Type II error (beta) were prefixed at 03, since lower levels entail taking a larger number of samples. Thesequential plans were then generated using the SEQUAN computer program of Talerico and Chapman (1970). During field operation on not more than 50 ha at a time, it is suggested that at least ten hills should be examined visually before recommending any pest management action. Simultaneous sampling of pests and predators enables status of predators' populations to be considered before recommending any decision.
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