Dispersion and Binomial Sequential Sampling Plan for Lesser Date Moth Batrachedra amydraula (Lepidoptera: Batrachedridae) Infesting Date Palm Plantations

The Lesser Date Moth (LDM) Batrachedra amydraula (Lepidoptera: Batrachedridae) is a serious pest of fruits of date palm trees that causes economic losses in nearly all growing regions globally. As one of the main methods for controlling this pest, overuse of broad-spectrum insecticides is applied. Population sampling methods are fundamental in the chemical control-based IPM system, minimizing the negative effects of insecticides on the environment. A tentative sampling method for LDM is recommended; however, conventional sampling schemes are complained due to the time-consuming. Alternatively, binomial sequential sampling plans are often more efficient and may allow sampler to fast classify pest infestations and make a control decision. The objectives of this study were to determine the spatial distribution and develop binomial sequential sampling for fast reliable estimation of LDM infestation on date palms. Throughout the province of Basra, Iraq, eighty-four 1 ha date palm orchards were sampled from 2017 to 2019. The results of spatial distribution pattern analyses by using Taylor’s power law (a = 0.0695 and b = 1.4041) indicated that LDM on sampling units (date palm spikelets) were highly aggregated in date palm orchards. The mean vs. proportion infested (PT-m) (T= 0 to 5) models for LDM infesting sampling units (lower leaves) revealed relatively strong fits for LDM. Binomial sequential sampling plans for LDM on date palms were developed for action thresholds of 0.10, 0.15, 0.25, and 0.35 proportions of spikelets with at least three infested fruit (T=3). Binomial sequential sampling plans were validated using RVSP software by the evaluation of operating characteristics (OC) and average sample number (ASN) functions. We recommend a minimum sample size of 12 and sampling efforts should be terminated at 90 samples for these sampling plans.