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The adverse effects of intensive synthetic insecticide use present the challenge of finding pest-resistant cultivars in economically important plants. Since intrinsic characteristics of cultivars can influence the population dynamics of specialist insects, this study evaluated the fitness of the diamondback moth, Plutella xylostella(L.) (Lepidoptera: Plutellidae), on different genotypes of collard green (Brassica oleraceaevar. acephalaL.) using fertility life table parameters. Neonate larvae were reared to adulthood feeding daily on leaves from each collard green genotype. Adults originating from larvae fed on leaves from genotype 8 H had shorter lifespans compared to those fed on other genotypes. The shortest oviposition period was observed in 14 N (3.37 days), while the longest was observed in 1 A (10.10 days). Lower oviposition rates were observed on 8 H (38.3 eggs/female), 14 N (42.7 eggs/female), and 9 I (44.5 eggs/female) compared to 1 A (228.0 eggs/female). Moths reared on genotypes 8 H and 1 A exhibited the lowest (7.02 offspring per individual) and highest (69.0 offspring per individual) net reproductive rate (R0), respectively. The lowest intrinsic rate of increase (rm) were obtained when larvae fed on genotypes 8 H (0.05 days−1) and 14 N (0.07 days−1). These results suggest that intrinsic characteristics of B. oleraceaecan impact the longevity and reproductive potential of P. xylostella. Specifically, genotypes 32 GUA, 2 B, and HS resulted in low adult emergence, while 8 H, 9 I, 14 N, and HI CROP genotypes negatively affected the performance of this pest.

The whitefly, Bemisia tabaciMediterranean (MED), is an invasive pest of several crops, including soybeans. The objective of this study was to evaluate the resistance of soybean genotypes to B. tabaciMED, in addition to the influence of possibly related physical and morphological factors. A no-choice test was carried out with 90 soybean genotypes. Subsequently, 35 materials were selected for further no-choice and multiple-choice tests. Trichomes and leaf color of plants were observed, with the aim of correlating these factors with the preference and colonization of B. tabaciMED. The genotypes KS 4202, TMG 1188 RR, M 7739 IPRO, 65l65 IPRO, and PI 229358 were the least preferred by adults of B. tabaciMED. In the multiple-choice test, the lowest numbers of eggs and nymphs per square centimeter were observed for the genotypes Dowling, PI 229358, IAC 24, KS 4202. The genotypes IAC 19, TMG 1288 RR, TMG 1182 RR, 99R09, Dowling, and TMG 2375 IPRO presented the lowest numbers of eggs and nymphs in the no-choice assay. Plants with higher trichome density were preferred by adults of B. tabaciMED and, consequently, were more heavily colonized by these insects. Plants with leaves of lower luminosity and reduced green and yellow intensity were more attractive to the whiteflies. In summary, genotypes IAC 24, IAC 19, Dowling, 99R09, TMG 1182 RR, TMG 1288 RR and TMG 2375 IPRO exhibited lower colonization by B. tabaciMED in both assays, thus indicating their potential as promising sources of resistance to B. tabaciMED.

Corn, Zea mays (L.), is one of the most expressive crops in Brazil, due to its wide-ranging uses as animal feeding, biofuel production or used for human consumption. However, there is a huge gap between the actual yield and the natural yield potential of the crop, due to insects' attack. Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae) is a key corn pest in seed producing regions, due to its attack on corn ears. Plant resistance is a valuable tool for Integrated Pest Management systems and may maintain insect populations at a level that is below an economic or damage threshold. This study aimed to evaluate the biological performance of L. zonatus in different corn genotypes, under laboratory conditions, searching for possible characterization of antibiosis/antixenosis. To achieve this goal, ten nymphs (1st instar) were transferred to polyvinylchloride (PVC) ring containing a corn ear (R6) of each genotype. Each ring corresponded to one replicate, for a total of five replicates per genotype in a completely randomized design. The parameters assessed included the duration of each instar, nymphal period, nymphal survival (%), percentage of mortality of each nymphal stage, adult longevity, and adult weight. The results demonstrate that XB 8018 Bt, 30F53, IAC Airan, XB 8030 and 30F53 YHR genotypes reduced the mean survival and caused high mortality of L. zonatus nymphs at the second instar (above 75.00%) indicating the occurrence of antibiosis/antixenosis. The higher mortality rates were observed at the second nymphal instar. [ABSTRACT FROM AUTHOR]

Whiteflies (Hemiptera: Aleyrodidae) comprise a group of phytophagous insects, with worldwide distribution. This group has 1,556 described species, with members concentrated in the tropics. In Brazil, as the literature on species of Aleyrodidae and associated plants is limited, our study presents species of whiteflies and their host plants collected in some Brazilian regions. New host plants or new occurrence locations for species already known in the country are presented, in addition to the record of Aleurotulus laneus Martin, a species not yet reported in Brazil. [ABSTRACT FROM AUTHOR]

The soybean looper Chrysodeixis includens is one of the main defoliating pests of soybean cultures in Brazil. This work aimed to evaluate the effect of offering different soybean genotypes to this insect to verify the occurrence of antixenosis. In a greenhouse, assays were carried out to determine the attractiveness of C. includens adults given free-choice tests. This experiment used a randomized block design with five replicates. A second experiment assessed oviposition preference using no-choice tests, employing a completely randomized design with five replicates. Seventeen soybean cultivars were used; several of these had previously been reported as carriers of resistance to more than one species of insect. In the laboratory, a morphological analysis was carried out by quantifying the number of trichomes on leaf surfaces and evaluating the color of the leaf blade of the germplasm. In the attractiveness assay, genotypes 'IAC 19', 'IAC 18', 'IAC 23', L1-1-01, PI 274453, PI 229358, PI 171451, 'IAC 100', 'IAC 24', 'IAC 17' and IAC 74-2832 were classified as repellents. In the oviposition preference experiment, PI 171451, PI 274453, 'IAC 18', L1-1-01 and 'IAC 23' showed the fewest eggs. The high density of trichomes presented by the genotypes PI 227687 and PI 274453 stand out as a possible C. includens resistance factor. The genotype L1-1-01 presented intermediate luminosity (L*) and more intense green (a*) and yellow (b*) colors compared to other genotypes. There was no correlation between oviposition and trichome density or leaf coloration. [ABSTRACT FROM AUTHOR]

The aim of this study was to select forage grasses with potential resistance to Mahanarva fimbriolata by assessing effects on insect. No-choice assays were conducted with 12 genotypes and laboratory-reared insects. The following parameters were assessed: mortality and duration of the nymphal stage; adult weight and longevity; pre-oviposition period; number of eggs/female; viability and duration of the embryonic period. As main result it was verified that the mortality of nymphs reared on Panicum maximum cv. Paredão is almost complete and that this forage grass may be characterized as resistant to this insect by antibiosis. Further, the grasses can be divided into three groups following a cluster analysis: P. maximum cv. Aries, Setaria sphacelata cv. Kazungula, Brachiaria humidicola, A. gayanus and P. maximum cv. Aruana, which are insect-resistant grasses; Brachiaria decumbens cv. Basilisk, B. dictyoneura, B. brizantha cv. MG-4 and B. ruziziensis, which are moderately resistant grasses; and B. brizantha MG-5 and B. brizantha ecotype BB185, which are susceptible grasses. [ABSTRACT FROM AUTHOR]

Some species of pentatomids stink bugs have global economic importance, damaging various plant species during the vegetative and reproductive phases. Dichelops melacanthus (Dallas) (Hemiptera: Pentatomidae), known as the green-belly stink bug, is part of the soybean stink bug complex in Brazil and has increasing importance in crops, with potential to reduce crop yield. This polyphagous stink bug has been registered in 29 plant species belonging to 10 plant families which include cultivated and non-cultivated plants. Plant resistance is a valuable tool in integrated pest management and may reduce insect populations below economic injury level. This study characterized the resistance of 17 soybean genotypes to the green-belly stink bug. All of the materials affected the biological performance of the green-belly stink bug, but PI 227687; 'IAC 100'; PI 171451; IAC 78-2318; D 75-10169; IAC 74-2832; 'IAC 23' and 'IAC 24' caused mortality above 80% in the second instar. 'IAC 17'; 'IAC 18'; PI 171451; PI 274454; 'Conquista' and 'IAC 19' decreased the longevity of adults of D. melacanthus, showing the same mechanism of resistance. PI 227687 did not allow any insects to complete the immature stage. These results are unprecedented for the species D. melacanthus and can assist breeding programs that focus on resistance to members of the stink bug complex in soybean. [ABSTRACT FROM AUTHOR]

The aim of this study was to gather data on the incidence of fungi associated with peanut seeds stored in their pods, before being processed by the State of São Paulo seed-producing companies, and the relation of the fungi to the seed damage caused by insects and to the quality of the stored seeds. Samples were taken from seed lots of cultivars IAC 886 and IAC 503 stored by these companies at the beginning and end of a six-month storage period. The peanut seeds were shelled and half of each sample was treated with fludioxonil + metalaxyl. Untreated and treated seeds were analyzed for moisture content, germination, vigor and health. The following insects were found to damage the peanut seeds: Cyrtomenus mirabilis (Perty) (Hemiptera: Cydnidae) and Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae). Both species reduced seed quality. When present, fungi of the genera Aspergillus, Fusarium, Penicillium and Rhizopus infected seeds and seedlings during the germination process and were considered the main limiting factor for obtaining normal seedlings. Nevertheless, despite their presence, peanut seeds maintained their germination capacity and vigor after six months of storage in their pods. [ABSTRACT FROM AUTHOR]

Copyright of Bragantia is the property of Instituto Agronomico de Campinas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bragantia is the property of Instituto Agronomico de Campinas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bragantia is the property of Instituto Agronomico de Campinas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bragantia is the property of Instituto Agronomico de Campinas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bragantia is the property of Instituto Agronomico de Campinas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bragantia is the property of Instituto Agronomico de Campinas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bragantia is the property of Instituto Agronomico de Campinas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)