Forecasting Brassica napus production under climate change with a mechanistic species distribution model.

Brassica napus, a versatile crop with significant socioeconomic importance, serves as a valuable source of nutrition for humans and animals while also being utilized in biodiesel production. The expansion potential of B. napus is profoundly influenced by climatic variations, yet there remains a scarcity of studies investigating the correlation between climatic factors and its distribution. This research employs CLIMEX to identify the current and future ecological niches of B. napus under the RCP 8.5 emission scenario, utilizing the Access 1.0 and CNRM-CM5 models for the time frame of 2040-2059. Additionally, a sensitivity analysis of parameters was conducted to determine the primary climatic factors affecting B. napus distribution and model responsiveness. The simulated outcomes demonstrate a satisfactory alignment with the known current distribution of B. napus, with 98% of occurrence records classified as having medium to high climatic suitability. However, the species displays high sensitivity to thermal parameters, thereby suggesting that temperature increases could trigger shifts in suitable and unsuitable areas for B. napus, impacting regions such as Canada, China, Brazil, and the United States.

Acute and Chronic Toxicity of Neem Oil to the Endoparasitoid Palmistichus elaeisis (Hymenoptera: Eulophidae).

Palmistichus elaeisis Delvare and LaSalle 1993 (Hymenoptera: Eulophidae) and neem oil are two control alternatives for the integrated management of defoliating lepidopterans. The aim of this study was to evaluate the acute and chronic toxicity of neem oil compared to the synthetic insecticide deltamethrin, on the endoparasitoid P. elaeisis, in generations F0, F1, F2, and F3. Females of P. elaeisis were exposed to neem solutions at concentrations of 0, 1.87, 3.75, 7.50, 15.00, 30.00, and 60.00 mg ml-1, to determine the dose-response relationship and estimate the neem LC50. The sublethal effects on the parasitoid P. elaeisis in generations F0 to F3 were evaluated with these same concentrations of neem and 0.033 mg ml-1 of deltamethrin. The neem LC50 was estimated at 3.92 mg ml-1. The LC50 for P. elaeisis is 3.83 times lower than that recommended by the neem manufacturer for pest control, demonstrating high acute toxicity to this natural enemy. The chronic toxicity of both the commercial dose and those below it to P. elaeisis caused low sublethal effects. The correct concentration of neem oil in pest control is important, and its use should be performed with caution in integrated pest management programs using the endoparasitoid P. elaeisis to avoid causing interference between the two pest control techniques.

Selectivity of deltamethrin doses on Palmistichus elaeisis (Hymenoptera: Eulophidae) parasitizing Tenebrio molitor (Coleoptera: Tenebrionidae).

Insecticides are the main method of controlling lepidopteran pests of eucalyptus plantations and those selective to natural enemies, such as the endoparasitoid Palmistichus elaeisis Delvare et LaSalle (Hymenoptera: Eulophidae), are preferable. The objective of this study was to evaluate the selectivity and effects on biological parameters of the insecticide deltamethrin, registered for the control of defoliator caterpillars of eucalyptus, to the parasitoid P. elaeisis aiming the rational use of this insecticide and its compatibility with parasitoids. The experiment was in a completely randomized design. The treatments were the doses of 0.64, 1.40, 3.10, 6.83, 15.03, 33.05, 72.7 and 160 mg a.i./L of deltamethrin and the control (distilled water) with 10 replications, each with a pupae of the alternative host Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae) exposed by the immersion method. The parasitism, biological cycle, emergence, longevity, head width and metatibia length of the natural enemy were evaluated. Deltamethrin reduced parasitism and the emergence rates of P. elaeisis. The duration of the biological cycle of this parasitoid, emerged from T. molitor pupae exposed to 15.03 mg a.i./L of deltamethrin, was higher. The morphometric parameters of P. elaeisis exposed to the doses of 0.64 and 1.40 mg a.i./L of the insecticide were lower. However, the morphometric parameter values were higher with the doses above 3.10 mg a.i./L than in the control. The parasitism and emergence of P. elaeisis were also reduced by the deltamethrin doses lower than the commercially recommended one and therefore, this insecticide is not selective for this natural enemy.