First report and biological characteristics of Heterorhabditis amazonensis in the state of Paraná, Brazil.

Entomopathogenic nematodes (EPNs) from Heterorhabditidae and Steinernematidae families are extensively used to control insect pests. In Brazil, however, relatively few studies have identified and characterized these entomopathogens. The objective of this study was to identify and characterize an EPN isolate obtained from soil samples collected in the state of Paraná, Brazil. An isolate (UEL 08) of Heterorhabditis was detected in a soil sample collected from a pasture area cultivated with Brachiaria grass in Londrina, state of Paraná, Brazil (23°34'311''S, 050°58'298''W), using the insect-baiting technique with Galleria mellonella larvae as hosts. The nematode was identified through morphometric studies and molecular analyses based on amplification of the rDNA ITS region. Although we identified certain morphometric differences compared with the original description, the molecular data indicated that the ITS sequence obtained for the UEL 08 isolate is identical to the reference sequence of H. amazonensis (DQ665222) and presented 100% similarity. Thus, the findings of our morphological and molecular studies confirmed that the isolated nematode is H. amazonensis, which is the first time this species has been registered in Paraná. Study of the biological characteristics of H. amazonensis (UEL 08) revealed that the isolate has two distinct life cycles - one short (216 h) and the other long (288 h) - and produces two generations in both cycles. We observed that H. amazonensis (UEL 8) was pathogenic and virulent to the three evaluated hosts, although with different virulence against these hosts. The larvae of G. mellonella and Alphitobius diaperinus were more susceptible than adult Dichelops (Diacereus) melacanthus, with 100%, 85%, and 46% mortality, respectively. Furthermore, an in vivo production assay revealed a mean daily yield of 3.4 × 103 infective juveniles/g host larvae.

Combined Application of Entomopathogenic Nematodes and Insecticides in the Control of Leaf-Miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) on Tomato.

The present research aimed to investigate the compatibility of entomopathogenic nematodes (EPNs) and registered insecticides for the control of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in the tomato crop, as well as the susceptibility of pupae of T. absoluta to EPNs combined with different percentages below the recommended dose of compatible chemical insecticides in laboratory conditions and in the greenhouse. The species of EPN used was Heterorhabditis amazonensis JPM4. The insecticides used were Actara®, Premio®, and Warrant®. In the compatibility test between the EPNs and insecticides, the viability and infectivity of the nematodes after contact with the insecticides were evaluated. An assessment of the efficacy of the combined application of different doses of the insecticides and the EPNs on T. absoluta was carried out in the laboratory and greenhouse. The efficacy of the combined application of the insecticides and the EPNs on T. absoluta via soil was carried out at application intervals of 1 and 2 weeks. The EPNs were compatible with the three insecticides tested. In the laboratory, there was an additive effect of the combined application of insecticides and H. amazonensis as the dose of the products increased. In the greenhouse assay, the combined application of EPNs and insecticides induced mortality above 48%, and the combined application of EPNs and Warrant® 75% presented 60% of mortality. The weekly and fortnightly applications were effective in controlling T. absoluta, and there was no difference between the insecticides tested when applied together with the nematodes.

Mini tomato genotypes resistant to the silverleaf whitefly and to two-spotted spider mites.

The mini tomato production has expanded, becoming an amazing alternative for enterprise. Despite all commercial potential, the cultivation has the occurrence of pests as main obstacle during the crop development. Nowadays, there are no researches that aimed obtaining genotypes with high acylsugar content, capable of providing a broad-spectrum resistance to pests. This study aimed the selection of mini tomato genotypes, with high acylsugar content, and checking the resistance level to the silverleaf whitefly [Bemisia tabaci (Gennadius)] and to the two-spotted spider mites (Tetranychus urticae Koch). Sixteen genotypes were evaluated, from which 12 were on the generation F2BC1, originated from the interespecific cross between Solanum pennellii versus Solanum lycopersicum L. and 4 were check treatments, being three of cultivated tomatos (cv. Santa Clara, UFU-02, and UFU-73) and the wild accession LA-716 (S. pennellii). The variables analyzed were acylsugar content, repellency to the silverleaf whitefly, repellence to the two-spotted spider mites, and density of glandular trichomes. The genotypes UFU-22-F2BC1#9 and UFU-73-F2BC1#11 have high acylsugar content and both are resistant to the pests that were evaluated. New studies must be conducted seeking for inbred lines, obtained from the selected genotypes, aiming to get commercial hybrids with high acylsugar content.