Melon genotypes with resistance to Liriomyza sativae Blanchard (Diptera: Agromyzidae).

The vegetable leaf miner (Liriomyza sativae) is considered one of the main melon pests, causing serious problems for producers in all growing regions. A promising type of pest control has been use of resistant cultivars, in isolation or associated with other types of control. This study aimed to evaluate the resistance of melon genotypes to L. sativae. Twenty-one melon genotypes and one commercial "Goldex" hybrid (susceptibility pattern) were evaluated in two experiments. In the first experiment, we observed the non-preference of L. sativae for oviposition and feeding by quantifying the number of eggs and feeding punctures, both on the adaxial side and on the abaxial face of the leaves. In the second experiment, we observed the antibiosis effect through L. sativae larval and pupal viability. Genotype CNPH 06-1047-341 showed the lowest preference for oviposition (high resistance), with low egg values on both leaf sides (0.3 eggs/plant). In genotypes CNPH 06-1047-313, CNPH 06-1047-346, CNPH 11-1071-27, CNPH 11-1071-39, CNPH 11-1071-43, and CNPH 11-1071-53, we observed a higher preference for the adaxial side, whereas for the other genotypes and the commercial hybrid there was no discrimination between leaf sides. In relation to antibiosis, genotypes CNPH 06-1047-339, CNPH 06-1047-333, CNPH 06-1047-330, CNPH 06-1047-334, CNPH 06-1047-331, CNPH 06-1047-343, CNPH 10-1056-313, CNPH 06-1047-346, and CNPH 06-1047-341 presented lower larval and pupal viability. Genotype CNPH 06-1047-341 was the least preferred for oviposition and feeding and the most promising as a source of resistance to L. sativae.

Small-Scale Production of Amblyseius tamatavensis with Thyreophagus cracentiseta (Acari: Phytoseiidae, Acaridae).

Amblyseius tamatavensis, a predatory mite, has been mentioned as potentially useful for the control of Bemisia tabaci. The objective of this work was to compare the production rates of A. tamatavensis in closed units containing T. cracentiseta as food, at different combinations of numbers of predator inoculated, periods of production and volumes of rearing units. Final predator densities increased with increasing production periods up to 30-45 days, reducing afterward. Likewise, maximum final densities increased with increasing predator inoculation levels, up to 200 predators per rearing unit. The results led us to select the proportion of 150 predators per unit for a production period of 30 days to evaluate the effect of the size of the experimental unit. Then, in the second part of the study, a direct relationship was observed between volume and final predator density (y = 8610.25x + 2166.04; R2 = 0.99; p < 0.0001). It was also calculated that ri value was quite stable (0113-0.119), with a calculated value of 0.115 at all volumes of rearing units. It can be concluded that progressively larger numbers of predators can be obtained with progressively larger rearing units.

Dispersal of Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) in cabbage, cucumber, and sweet corn.

Abstract: The dispersion capacity is fundamental to establish a biological control program with parasitoids. This information is used to determine the efficiency and the number of release points. Thus, the objective of this work was to determine the dispersion and to estimate the number of release points of Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae), in sweet corn, cucumber and cabbage in the Ceará State. The experiments were carried out in areas of maize with four leaf pairs (V4) and eight leaves pair (V8), stacked and cabbage. Unviable eggs of an alternative host were distributed in concentric circles of radius 2.5; 5.0; 9.0 and 12.0 m. Mean dispersal distance in the V4 stage maize was 4.7 m with a dispersion area of 48.6 m2, parasitism index of 18.4%, requiring 206 points/ha. In the V8 stage maize, the mean distance was 5.9 m, dispersion area of 60.3 m², mean parasitism index of 22.7% and 166 release points/ha. For the cucumber culture the mean distance was 6.0 m, dispersion area 62.2 m², mean parasitism index of 21.1% and 161 release points/ha. For cabbage the mean distance was 5.6 m, dispersion area of 56.8 m², mean parasitism index of 22.1% and 176 release points/ha.

Population dynamics and infestation of Holopothrips fulvus Morgan (Thysanoptera: Phlaeothripidae) in dwarf cashew genotypes.

The objective of this study was to evaluate the Holopothrips fulvus Morgan (Thysanoptera: Phlaeothripidae) population dynamics and to identify dwarf cashew genotypes less infested by the pest in 2015 and 2016, under field conditions. H. fulvus population evaluations were carried out by monthly observations in the plants and using a score scale varying from 0 to 4. H. fulvus infestation occurred from October to December, and in the cashew genotypes CAP 112/8, CAP 121/1, CAP 131/2, CAP 145/2, CAP 145/7, CAP 128/2, CAP 120/4, CAP 123/6, CAP 130/1, and CAP 157/2 was dependent on the flowering period of the crop in 2015. In 2016, there was dependence in all evaluated genotypes between H. fulvus infestation and the cashew flowering period. In 2015, no significant differences were observed between the evaluated genotypes regarding H. fulvus infestation. In 2016, genotypes CAP 105/5, CAP 143/7, CAP 150/3, CAP 155/2, CAP 158/8, CAP 161/7, CAP 163/8, CAP 31, CAP 71, CAP 92, CAP 113, CAP 120, CAP 155, CAP 165, CAP 106/1, CAP 111/2, CAP 127/3, CAP 157/2, and BRS 226 were less infested. H. fulvus occurs from October to December and we could identify the dwarf cashew genotypes less infested by the pest.

Bioinsecticide-predator interactions: azadirachtin behavioral and reproductive impairment of the coconut mite predator Neoseiulus baraki.

Synthetic pesticide use has been the dominant form of pest control since the 1940s. However, biopesticides are emerging as sustainable pest control alternatives, with prevailing use in organic agricultural production systems. Foremost among botanical biopesticides is the limonoid azadirachtin, whose perceived environmental safety has come under debate and scrutiny in recent years. Coconut production, particularly organic coconut production, is one of the agricultural systems in which azadirachtin is used as a primary method of pest control for the management of the invasive coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae). The management of this mite species also greatly benefits from predation by Neoseiulus baraki (Athias-Henriot) (Acari: Phytoseiidae). Here, we assessed the potential behavioral impacts of azadirachtin on the coconut mite predator, N. baraki. We explored the effects of this biopesticide on overall predator activity, female searching time, and mating behavior and fecundity. Azadirachtin impairs the overall activity of the predator, reducing it to nearly half; however, female searching was not affected. In contrast, mating behavior was compromised by azadirachtin exposure particularly when male predators were exposed to the biopesticide. Consequently, predator fecundity was also compromised by azadirachtin, furthering doubts about its environmental safety and selectivity towards biological control agents.

Olfactory response of predatory mites to vegetative and reproductive parts of coconut palm infested by Aceria guerreronis.

The phytophagous mite Aceria guerreronis Keifer is an important pest of coconut worldwide. A promising method of control for this pest is the use of predatory mites. Neoseiulus baraki (Athias-Henriot) and Proctolaelaps bickleyi Bram are predatory mites found in association with A. guerreronis in the field. To understand how these predators respond to olfactory cues from A. guerreronis and its host plant, the foraging behavior of the predatory mites was investigated in a Y-tube olfactometer and on T-shaped arenas. The predators were subjected to choose in an olfactometer: (1) isolated parts (leaflet, spikelet or fruit) of infested coconut plant or clean air stream; (2) isolated parts of non-infested or infested coconut plant; and (3) two different plant parts previously shown to be attractive. Using T-shaped arenas the predators were offered all possible binary combinations of discs of coconut fruit epidermis infested with A. guerreronis, non-infested discs or coconut pollen. The results showed that both predators were preferred (the volatile cues from) the infested plant parts over clean air. When subjected to odours from different infested or non-infested plant parts, predators preferred the infested parts. Among the infested plant parts, the spikelets induced the greatest attraction to predators. On the arenas, both predators preferred discs of coconut fruits infested with A. guerreronis over every other alternative. The results show that both predators are able to locate A. guerreronis by olfactory stimuli. Foraging strategies and implications for biological control are discussed.