Conventional sampling plan for the green leafhopper Empoasca kraemeri in common beans

Abstract

A conventional sampling plan for the leafhopper Empoasca kraemeri Ross & Moore (Auchenorrhyncha: Cicadellidae) in common beans (Phaseolus vulgaris L.) is presented based on samples from 51 commercial fields. The research encompassed three phases. The first phase had the objective of determining the most suitable leaf to be used as a precise and representative sampling unit. In the second phase of the project, the available sampling methods for E. kraemeri were compared, including the approach identified in the first phase. In the third phase, the theoretical frequency distribution of the sampling data was assessed and the number of samples necessary for the sampling plan was established. The best leaves to sample adult leafhoppers were the fourth and the fifth from the apex, while the best leaf for sampling nymphs was the fifth from the apex. The best sampling technique for nymphs and adults was the beating of the apical leaves against a plastic tray. The sampling data obtained with this technique were fit to a negative binomial distribution with common aggregation parameter for adults (K common ¼ 1.04) and nymphs (K common ¼ 0.47). This sampling plan required 16.8 and 31.2 min to be carried out at an expense of US$ 0.31 and US$ 0.54 for sampling adults and nymphs in a field, respectively.

Feasible sampling plan for Bemisia tabaci control decision‐making in watermelon fields

“…Sampling speed, accuracy and representativeness were used in the selection of the sampling units . The frequencies of occurrence of each leaf in the stem were initially calculated using Eqn (1): …”

“…Sampling units with positive and significant levels of correlation between the relative (insects leaf −1 ) and absolute (insects stem −1 ) densities according to the t test at P < 0.05 were selected based on the representativeness criterion …”

“…The sampling unit and technique to be used in evaluating pest populations in fields are determined in the conventional sampling plan. Furthermore, the number of samples to be used in evaluations of the intensity of pest attacks on crops is determined in the conventional sampling plan …”

“…Watermelon plants have stems, which have several leaves from the apex to the base. Direct counting and leaf beating on white plastic trays followed by counting the insects on the bottom of the tray are some of the sampling techniques most used with sap‐sucking insects, including B. tabaci . Optimal sampling units and techniques to be used in sampling plans should be accurate and representative and should enable fast evaluations of the intensity of pest attacks on crops.…”

“…Optimal sampling units and techniques to be used in sampling plans should be accurate and representative and should enable fast evaluations of the intensity of pest attacks on crops. The use of accurate sampling units and techniques provides sampling with a low degree of variation, thereby generating feasible, fast and low‐cost sampling plans . The use of representative sampling units enables the intensities of pest attacks to be determined using sampling plans similar to those occurring throughout the crop cycle …”