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).

Deltamethrin, a member of the pyrethroids, one of the safest classes of pesticides, is among some of the most popular and widely used insecticides in the World. Our objective was to synthesize an oxabicyclolactone 6 and five novel pyrethroids 8–12 from readily available furfural and D-mannitol, respectively, and evaluate their biological activity against four insect species of economic importance namely A. obtectus, S. zeamais, A. monuste orseis, and P. americana. A concise and novel synthesis of 6,6-dimethyl-3-oxabicyclo[3.1.0]hexan-2-one (6) from furfural is described. Photochemical addition of isopropyl alcohol to furan-2(5H)-one afforded 4-(1'-hydroxy-1'-methylethyl)tetrahydro-furan-2-one (3). The alcohol 3 was directly converted into 4-(1'-bromo-1'-methylethyl)-tetrahydrofuran-2-one (5) in 50% yield by reaction with PBr₃ and SiO₂. The final step was performed by cyclization of 5 with potassium tert-butoxide in 40% yield. The novel pyrethroids 8–12 were prepared from methyl (1S,3S)-3-formyl-2,2-dimethylcyclopropane-1-carboxylate (7a) by reaction with five different aromatic phosphorous ylides. Compounds 6–12 presented high insecticidal activity, with 6 and 11 being the most active. Compound 6 killed 90% of S. zeamais and 100% of all the other insects evaluated. Compound 11 killed 100% of all insects tested.

There is increasing demand for new products for vegetable pest management. Thus, the aim of this study was to assess the toxicity of pyrethroids with acid moiety modifications to measure the insecticidal activity of these compounds on the lepidopteran vegetable pests Diaphania hyalinata (L.) (Lepidoptera: Pyralidae) and Asciamonuste (Latreille) (Lepidoptera: Pieridae) and evaluate their selectivity for the predatory ant Solenopsis saevissima (F. Smith) (Hymenoptera: Formicidae) and pollinator Tetragonisca angustula (Latreille) (Hymenoptera: Apidae: Meliponinae). Racemic mixtures of five new pyrethroids (30 µg molecule mg⁻¹ insect body weight) resulted in high (100%) and rapid (stable LD₅₀ after 12 h) mortality in D. hyalinata and A. monuste. In A. monuste, the trans-pyrethroid [12] isomer showed similar toxicity to permethrin. For D. hyalinata, the trans-pyrethroid [9] isomer and cis-pyrethroid [10] isomer were as toxic as permethrin. Due to their low selectivity, these new pyrethroids should be applied on the basis of ecological selectivity principles to minimize impacts on nontarget organisms S. saevissima and T. angustula.

Soybean, Glycine max (L.) Merrill, is the most cultivated crop worldwide. Recently, thrips (Thysanoptera: Thripidae) has caused of up to 17% production losses to this crop. To improve its management, economic injury levels (EIL) are key tools in supporting decision-making systems in integrated pest management (IPM) programs. The EIL depend on the technology used for insecticide application. In this regard, pesticide treatment on soybean crops can be successfully performed by aircraft or tractors, especially among major producers (e.g., Brazil, the United States, Argentina, and China). There are currently no economic injury levels (EIL) for thrips in soybean crops. Therefore, the objective of this work was to determine economic injury levels for thrips in soybean, with insecticide applications by aircraft and by tractors. The study was carried out in four commercial soybean crops for two years. Frankliniella schultzei and Caliothrips phaseoli were observed attacking soybean plants. The EIL were 4.53 and 3.43 thrips sample^-1 for insecticide application with aircraft and tractor, respectively. The economic injury levels, established in this study, can be used in integrated pest management program for soybean crops.