The production of fruits and seeds of many crops is increased when bees visit their flowers pollinating them. The aim of this research was to study the pollination of pumpkins (Cucurbita maxima Duch. var. Exposição), to determine the diversity of insects visiting its flowers, the time and type of provision obtained and the effect of the visits on fruit set, fruit size and weight, and number of seeds. Apis mellifera L. accounted for 73.4% of the visits made by bees, collecting pollen during 34.5 s per flower and nectar in 43.9 s and 29.3 s from female and male flowers, respectively. Trigona spinipes (Fabr.) collected only nectar, during a mean time of 60.5 s per flower, and represented 26.6% of the visits by bees. Diabrotica speciosa (Germ.) only fed on the petals of the flower. When no insect visits occurred, there was no production of fruits. In the flowers with free visitation by insects, fruit set was 40%. The higher the number of visits, up to 16, by A. mellifera to female flowers, the greater was the fruit set, fruit size and weight, and number of seeds. In flowers visited by insects from the onset of anthesis until 9 a.m., fruit set was 35%. After 9 a.m., there was no fruit set, demonstrating the important role of A. mellifera as a pollinating agent of pumpkin, since it was the only insect visiting up to 9 a.m.

There is no use restriction associated with bees for many fungicides used in agriculture; however, this does not always mean that these pesticides are harmless for these non‐target organisms. We investigated whether the fungicide pyraclostrobin, which acts on fungal mitochondria, also negatively affects honey bee mitochondrial bioenergetics. Honey bees were collected from five hives and anesthetized at 4^oC. The thoraces were separated and mitochondria were isolated by grinding, filtering and differential centrifugation. An aliquot of 0.5 mg of mitochondrial proteins was added to 0.5 mL of a standard reaction medium with 4 mM succinate (complex II substrate) plus 50 nM rotenone (complex I inhibitor), and mitochondrial respiration was measured at 30°C using a Clark‐type oxygen electrode. Mitochondrial membrane potential was determined spectrofluorimetrically using safranin O as a probe, and ATP synthesis was determined by chemiluminescence. Pyraclostrobin at 0 to 50 μM was tested on the mitochondrial preparations, with three repetitions. Pyraclostrobin inhibited mitochondrial respiration in a dose dependent manner at concentrations of 10 μM and above, demonstrating typical inhibition of oxidative phosphorylation. Pyraclostrobin also promoted a decline in the mitochondrial membrane potential at doses of 5 μM and above and in ATP synthesis at 15 μM and above. We conclude that pyraclostrobin interferes with honey bee mitochondrial function, which is especially critical for the energy‐demanding flight activity of foraging bees.

Plants support numerous microorganisms within their tissues and the rhizosphere, and these microorganisms, known as the microbiota, can influence plant growth and health. Up to 40% of a plant’s photosynthetic metabolism may be invested in the rhizosphere. The microbiota is considered an extra genome that can be modulated to meet plant needs. Researchers have identified a set of genes from these microorganisms, known as the microbiome, which can be manipulated to enhance plant growth and health, improve nutrient absorption, reduce the need for chemical fertilizers, increase resistance to pathogens and pests, and increase stress tolerance. In particular, fungi exhibit large genetic and metabolic diversity and are often used to promote plant growth. For example, the fungus Purpureocillium lilacinum has been employed primarily as a biocontrol agent to manage nematodes, but some studies have suggested that it may also promote plant growth by increasing the efficiency of the plant in absorbing nutrients from the soil and providing phytohormones to plants. Therefore, the current review aims to summarize the existing literature on the use of this fungus in agriculture as nematodes control, and discuss its potential as a plant growth-promoter.