The pea leafminer, Liriomyza huidobrensis (Blanchard), is an important pest of tomato crops worldwide. Conventional sampling plans are the starting point for the development of pest control decision-making. The present study aimed to develop a conventional sampling plan for L. huidobrensis during the vegetative and reproductive stages of tomato (Solanum Lycopersicum L.). The best sampling unit for vegetative and reproductive stages of tomato crops was determined. The frequency distributions of L. huidobrensis densities in tomato crops were assessed, and the ideal number of samples to constitute the sampling plan was determined. The basal leaf of the middle section of the plant canopy was the best plant part for sampling. Pea leafminer densities were fitted to the negative binomial distribution with a common aggregation parameter (Kcommon = 0.7289) that represents all tomato fields. The sampling plan consists of 73 samples per field, irrespective of field size (1, 5, or 10 ha). Evaluations using this sampling plan were performed in 47 min, 1 h 9 min, and 1 h 25 min at a cost of US$1.74, US$2.54, and US$3.12 per sampling in fields of 1, 5, and 10 ha, respectively. The sampling plan developed in this study may lead to more well-informed decision-making for controlling L. huidobrensis in tomato fields up to 10 ha. Additionally, it is inexpensive (up to US$3.12 per sampling area), fast (up to 1 h 25 min per sampling area), and practical (it can be used in tomato crops at the vegetative and reproductive stages).

Melon (Cucumis melo L.; Cucurbitaceae) is one of the 10 most-consumed fruits in the world. The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is one of the most important pests in melon crops worldwide. Conventional sampling plans are the starting point to establish decisionmaking systems for integrated pest management (IPM) programs. The purpose of this study was to determine a conventional sampling plan for B. tabaci in melon crops with plants at the vegetative, flowering, and fruiting stages. The best sampling units for B. tabaci were the 5th and 6th most apical leaves of the plant vine. The best sampling technique was direct counting of adult whiteflies. The most appropriate frequency distribution to describe B. tabaci densities in melon fields was the negative binomial. Whiteflies on melon fields with plants at different phenological stages showed a common aggregation parameter (Kcommon = 0.9134). The optimal number of samples from the sampling plan was 72 samples per field with a maximum error of 15% in population determination. The sampling plan determined by this study can be used by farmers because it is a low-cost (US$5.27 per sampling), fast (39 minutes per sampling) and feasible (15% maximum evaluation error). The same sampling plan can be used with melon plants at the vegetative, flowering, and fruiting stages.

Maize is attacked by various pest species, including the key-pest of stored maize, Sitophilus zeamais (Coleoptera: Curculionidae). This study determined the LC50 and LD50 of neem-based insecticides (AzaMax® and Natuneem®) in comparison to a synthetic pyrethroid insecticide (Decis® 25 CE) to S. zeamais . The bioassays consisted of insects’ exposure alone (topical application with microsyringe) and exposure of both insects and seeds treated simultaneously. The final bioassays used four to six concentrations of each formulation per bioassay, diluted in distilled water. The bioassays were run with the use of 10 non-sexed adults of S. zeamais per replication and mortality was assessed after 48 h of exposure. The data regarding concentration and dose-mortality were analyzed by probit analysis. Both LC50 and LD50 were used to calculate LCR and LDR's and their respective confidence interval (CI). After using topical application, the bioassays yielded LD50-values of 51.32, 76.76 and 42.75 µL of AzaMax, Natuneem and Decis/g of insects, respectively. The bioassays with simultaneous exposure of both insects and seeds yielded LC50-values of 4.01, 4.46 and 0.41 µL of AzaMax, Natuneem and Decis/g of seeds, respectively. Regarding the fact that there were no significant differences between the LC50-values of the botanical insecticides, both of them can be used to manage S. zeamais infesting stored corn. The cost to treat maize and to obtain effective control of S. zeamais is cheapest for Decis<Natuneem<Āzamax. The LC50-values found in our study would be equivalent to use 8.02, 8.92 and 0.82 L of AzaMax, Natuneem and Decis/ton of seeds.