This study evaluated the effects of nitrogen fertilization and different types of planting material on the yield and fruit quality of pineapple (Ananas comosus var. comosus) cv. Smooth Cayenne under the edaphoclimatic conditions of the Northern region of Rio de Janeiro State, Brazil. The experiment was conducted in a randomized block design, arranged in a factorial scheme with four nitrogen rates, six types of planting material, and two harvest seasons (winter and summer). Based on the results, it can be inferred that slips provided higher yields and heavier fruits, whereas plants derived from crowns and suckers showed lower productivity. Increasing nitrogen rates promoted greater fruit mass and length, higher pulp percentage, and increased production of vegetative propagules. Fruits harvested in the summer showed higher soluble solids content (15.5 °Brix), greater pulp and juice percentages, and lower titratable acidity, which are desirable characteristics for fresh consumption. Despite the seasonal differences, fruit mass ranging from 1.5 to 2.0 kg met commercial standards for both processing and domestic markets. The soluble solids/titratable acidity ratio (15.8) was below the ideal range for fresh consumption. The combination of appropriate planting material and nitrogen fertilization contributes to higher production efficiency, cost reduction, and improved fruit quality.

The Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) has been studied and applied in controlling the fall armyworm, Spodoptera frugiperda. This pest serves as the primary host for in vivo replication of this biological control agent. For viral inoculation, the virus is introduced into an artificial diet, which is also used for large-scale host multiplication. In this study, we tested more cost-effective diets to optimize the viral inoculation stage. Each diet was treated with the virus and monitored daily for host mortality. Viral production parameters were subsequently quantified. Although the evaluated diets did not achieve the same yield levels as those used for large-scale S. frugiperda multiplication, the D7 diet showed similar cost-effectiveness to the D2 diet in terms of producing one dose per hectare. Additionally, larvae consuming diets higher in crude protein exhibited reduced viral polyhedra production.

Micropropagated plantlets, after removal from controlled laboratory conditions, require an acclimatization period. Adaptation to the new environment induces anatomical and physiological changes controlled by cellular processes. This study investigated the involvement of the primary proton transport systems of total membranes in pineapple root colonization by diazotrophic bacteria and in the development of plantlets treated with different nitrogen doses, allowing an understanding of nutrient absorption and accumulation dynamics. The experiment followed a randomized block design (RBD) in a factorial scheme (2 × 3 × 2), with two inocula (a mixture of diazotrophic bacteria containing Burkholderia sp. UENF 114111, Burkholderia silvatlantica UENF 117111, and Herbaspirillum seropedicae HRC 54, and another without bacteria), three urea doses (0, 5, and 10 g L⁻¹), and two evaluation (90 and 150 days) and bacterial counting times (30 and 150 days), with three blocks. Diazotrophic bacterial populations were lower in older plantlets. H⁺ transport mediated by P H⁺-ATPases changed with acclimatization time. Inoculation did not induce transport; however, the F_max of V H⁺-ATPase was lower without nitrogen fertilization. Nitrogen fertilization affected V H⁺-ATPase proton transport activity in root membranes. The presence of diazotrophic bacteria did not induce proton transport. On the other hand, nitrogen fertilization and acclimatization time affected the proton transport activity mediated by H⁺-ATPases isolated from roots of micropropagated pineapple.

The inoculation of viral entomopathogens in vivo requires study of each pathosystem. Several factors interfere in the cost of production and consequently in the availability of virus-based formulations. For the Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV), employed in the management of the fall armyworm Spodoptera frugiperda, factors such as host cannibal habit, temperature, and artificial diet of viral inoculation are important to research. In this work we propose to evaluate a diet based on textured soy protein, without heating during preparation, for viral inoculation and an artificial diet of simplified composition, based on wheat germ, to complete the feeding of larvaes during the stage of viral inoculation in groups of insects. S. frugiperda larvae were inoculated with SfMNPV virus in two diets: an artificial diet similar to that of mass rearing of the host and texturized soy protein at the following temperatures and respective ages: at 25 °C at 6 and 8 days after hatching and 31 °C at 4 and 6 days after larvae hatching. And, subsequently, viral inoculation was evaluated in a group of 300 larvae under different incubation times and temperature conditions, complementing feeding at this stage with a diet of simplified composition. The results show that it is possible to inoculate viruses without loss of viral polyhedra production in a textured soy protein-based diet and supplement the larvae diet with an artificial diet of simplified composition to complete the viral infection stage in groups of infected insects.

Programmed Cycle Pruning (PCP) in Arabica coffee can positively influence plant physiology by modifying plant architecture, promoting a more uniform distribution of branches and leaves, and altering microclimatic conditions within the canopy, particularly light incidence. These structural changes may contribute to improvements in plant performance and productivity. The objective of this study was to evaluate growth, yield, and physiological responses of Arabica coffee plants managed under PCP at different stem densities per hectare. The experiment was conducted in a randomized block design with four replications. Treatments were arranged in a 4 × 2 factorial scheme with an additional treatment representing the traditional pruning system. The factorial combination included four stem densities (4000, 8000, 12,000, and 16,000 stems ha⁻¹) and two data collection positions on the plant (lower and upper canopy strata). The evaluated variables included canopy diameter, plagiotropic branch length, number of inflorescences per branch, net photosynthetic rate (Anet), stomatal conductance (gs), leaf transpiration (E), vapor pressure deficit between leaf and air (VPDleaf/air), SPAD index, anthocyanin and flavonoid contents, and grain yield. PCP promoted greater uniformity in leaf gas exchange within the canopy and prevented the occurrence of “girdling”, which under traditional pruning reduced Anet in the upper canopy. Net photosynthesis increased with stem density under PCP. Although growth variables were similar between pruning systems, yield was higher under PCP, with a nonlinear response to stem density, indicating improved canopy gas-exchange uniformity and productivity in Arabica coffee cultivation.