توزیع مکانی و اندازه نمونه برای پایش Rhopalosiphum padi L. (Hemiptera: Aphididae) بر روی ذرت (Zea mays L.) در ایران

Maize (Zea mays L.) is one of the most important cereals in the world and one of the strategic crops in Iran. Many biotic and abiotic factors affect maize production and insect pests are one of the critical factors limiting maize production in the country. The bird cherry-oat aphid, Rhopalosiphum padi L. (Hemiptera: Aphididae) is one of the pests of maize in IRAN. Timely and effective monitoring and control of pests will prevent yield reduction, will tend to increase the production and help ensure the country's food security. Understating the spatial distribution of R. padi is critical for the development of reliable sampling plan. The study reported here aims to characterize the spatial distribution of the aphid in maize fields in Karaj (Alborz province, IRAN). Field sampling of populations (nymphs and adult) of R. padi on maize in the Karaj from 2022 to 2023 produced a data set consisting of 109 estimates of mean aphid density (m; number of aphids per plant) and variance (s2). Taylor's power law (s2=amb) regression was used to analyze the spatial pattern of R. padi population in maize. The distribution of populations of R. padi was highly aggregated, as indicated by a Taylor's-b value of 1.497. This high level of contagion meant that relatively large sample sizes would need to be collected to obtain an estimate of population density. Ruesink and Kogan’s equation was used for estimate the optimal sample size (the number of plants required) for four fixed precision levels, 0.10, 0.15, 0.20 and 0.25. Sample size requirements for estimation of population mean with fixed levels of precision were greatest for high-precision, but decreased in low-precision.