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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 oleraceae var. acephala L.) 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. oleraceae can 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.

Severe attacks of Brevicoryne brassicae (Hemiptera: Aphididae) on brassica crops may lead to a significant decrease in yield and can cause plant death. Host plant resistance is considered a valuable tool in integrated pest management and can assist in reducing the damage caused by aphids. This study evaluated the behavioral and biological parameters of B. brassicae in 37 Brassica oleracea (L.) var. acephala genotypes, and aimed to characterize the mechanisms of antixenosis and/or antibiosis. In antixenosis, plants were arranged in a circle inside an arena, releasing to the center one hundred adult aphids. The number of insects was evaluated at 1, 2, 3, 6, and 24 h after infestation. For antibiosis, 30 adults were confined inside each clip-cage on each genotype. The total number of nymphs; number of nymphs per adult per day; total nymphs until 10 d after the first nymph had been produced; duration of the pre-reproductive phase; duration of the reproductive phase; nymphal survival; adult longevity; nymph-adult period and nymphal mortality at 5, 7 and 10 d were evaluated. Several genotypes showed be less infested and more harmful to B. brassicae on collard greens. The genotypes 20T, 24X, 18R, 22V, 15O, 19S, 27VA, and 17Q were the least infested in the antixenosis 24 h free-choice test. 2B, 5E, 8H, 19S, 21U, 27VA, 30OP, PE, MGH, and TP genotypes prevented B. brassicae from completing nymphal period, indicating antibiosis and/or antixenosis expression. 4D, GAU, 20 T, 14 N, and MGI genotypes prevented the aphid from reaching the reproductive phase. These genotypes may be useful for breeding programs that focus on the resistance of collard greens to aphids.

Stink bugs are considered limiting pests to important crops worldwide. In Brazil, the green-belly stink bug, Dichelops melacanthus Dallas (Hemiptera: Pentatomidae), has become a key pest to the young phase of corn crop, being a problem especially when it succeeds soybean in the field. Injuries caused by this species vary from holes on new leaves to plant death in severe attacks. The main control technique used to this pest are seed treatment and insecticide spraying. Although both methods show some efficiency, factors as outbreaks in the resistance to insecticides and the different susceptibility existent among stink bugs population, leads to the search of other control strategies. Thus, less harmful tools to the environment and humans are highly desirable. In this sense, resistant plants appear as a valuable alternative for insect management, being compatible with other IPM methods. This study evaluated the resistance of 16 corn genotypes to D. melacanthus in order to characterize antixenosis and/or antibiosis expression. Antixenosis was accessed through preference multi-choice test with 5th instar nymphs. For antibiosis assessment, 60 2nd instar nymphs were confined on seedlings of 13 selected genotypes. Seedlings of IAC 8046, IAC 8390 and SCS 156 Colorado corn genotypes were less infested by D. melacanthus at 24 h after bugs were released indicating antixenosis expression. Genotypes IAC 8390 and JM 2M60 negatively affected some biological parameters of the green belly stink bug, indicating the occurrence of antibiosis. These genotypes can be useful to breeding programs focusing on corn resistance to stink bugs species.

The initial step in the successful implementation of a breeding program aimed at obtaining bruchid resistant beans lines is the identification of sources of resistance within a diverse germplasm. Here, a total of ninety two (92) Brazilian common bean genotypes were screened to identify promising sources of resistance to Zabrotes subfasciatus (Boheman) (Coleoptera: Chrysomelidae: Bruchinae), the primary insect pest of stored beans. The cultivars BRS Ametista and BRS Esplendor, as well as the bean lineages CHP 01-182-12-Uirapuru × Campeiro and CHP 04-241A-212-Guapo B. × Uirapuru exhibited the lowest oviposition rates. The genotypes BRS Ametista, CHP 01-182-12-Uirapuru × Campeiro and BRS Esplendor also showed the lowest average of adult emergence evidenced by the F 1 progeny. In contrast, genotypes BRS Ametista, CHP 05-282-04-Campeiro × Agudo, TB-17-02, CHC 01-167-1-03, IPR Uirapuru, CHIR 14, IPR Campos Gerais, CHIC 61-Cariocão, IAC Imperador, Arcelin 1, FAP-F3-2-SEL-IAC, CAV 17 EFM008, SCS 205-Riqueza, LP 13-634-preto, IAC Harmonia and Linhagem 110-IAC exhibited the lowest percentage of larval-pupal viability. Conversely, genotypes Arcelin 3, Arcelin 1, CHIN 19, CHV 05-268-02, LP 13-84-Carioca, CNFRs-15558-Rosinha, IPR Campos Gerais, CHC 01-175-1-Campeiro × IAC Tibatã, BRS Notável, IPR Uirapuru, BRS Estilo, IPR Quero-Quero, CAV 17 EFM0006, CHP 04-241A-212-Guapo B. × Uirapuru, BRS Esplendor, and CHP 01-182-12-Uirapuru × Campeiro were observed to significantly prolong the developmental time (cycle) of Z. subfasciatus , indicating the expression of antixenosis and/or antibiosis type resistance. Thus, these genotypes are promising sources of resistance to Z. subfasciatus , and further studies are recommended to elucidate the underlying mechanisms and genes involved.

Coleopterans within the family Coccinellidae play an important role in the biological control of Bemisia tabaci MEAM1 Gennadius (Hemiptera: Aleyrodidae), a worldwide pest. Here we report an initial assessment of the predatory capacity and biological aspects of a South American coccinellid, Delphastus davidsoni Gordon (Coleoptera: Coccinellidae) to B. tabaci immature stages under laboratory conditions. Within the 24 h after release, D. davidsoni adults were increasingly more attracted to and consumed six times more B. tabaci fourth instar nymphs than the remaining immature stages. Similarly, D. davidsoni larvae also had a greater consumption of B. tabaci fourth instar nymphs within 24 h after release. Within 10 days after larvae release, there were no significant differences in preference between the nymphal stages. Both D. davidsoni adults and larvae presented a better biological performance when fed with B. tabaci fourth instar nymphs. The larval developmental time and pupal survival for D. davidsoni was optimal when fed fourth instar nymphs. These findings highlight the potential for implementing D. davidsoni in integrated pest management (IPM) programs for B. tabaci and warrant further evaluation under greenhouse and semi-field conditions.

Coleopterans within the family Coccinellidae play an important role in the biological control of Bemisia tabaci MEAM1 Gennadius (Hemiptera: Aleyrodidae), a worldwide pest. Here we report an initial assessment of the predatory capacity and biological aspects of a South American coccinellid, Delphastus davidsoni Gordon (Coleoptera: Coccinellidae) to B. tabaci immature stages under laboratory conditions. Within the 24 h after release, D. davidsoni adults were increasingly more attracted to and consumed six times more B. tabaci fourth instar nymphs than the remaining immature stages. Similarly, D. davidsoni larvae also had a greater consumption of B. tabaci fourth instar nymphs within 24 h after release. Within 10 days after larvae release, there were no significant differences in preference between the nymphal stages. Both D. davidsoni adults and larvae presented a better biological performance when fed with B. tabaci fourth instar nymphs. The larval developmental time and pupal survival for D. davidsoni was optimal when fed fourth instar nymphs. These findings highlight the potential for implementing D. davidsoni in integrated pest management (IPM) programs for B. tabaci and warrant further evaluation under greenhouse and semi-field conditions. Os coleópteros da família Coccinellidae desempenham um importante papel no controle biológico de Bemisia tabaci MEAM1 Gennadius (Hemiptera: Aleyrodidae). Aqui relatamos uma avaliação inicial da capacidade predatória e aspectos biológicos do coccinelídeo sul-americano, Delphastus davidsoni Gordon (Coleoptera: Coccinellidae) para estágios imaturos de B. tabaci em condições de laboratório. Entre as 24 h após a liberação, os adultos de D. davidsoni foram mais atraídos e consumiram seis vezes mais ninfas de 4° ínstar de B. tabaci comparado aos demais estágios. Da mesma forma, as larvas de D. davidsoni também consumiram mais ninfas de 4° ínstar em 24 h após a liberação. Dez dias após a liberação das larvas, não houve diferença significativa na capacidade predatória entre os estágios ninfais. Ambos adultos e larvas apresentaram melhor desempenho biológico quando alimentados com ninfas de mosca-branca de 4° ínstar. O tempo de desenvolvimento larval e a sobrevivência das pupas também foram otimizados quando alimentados com ninfas de 4° ínstar. Esses achados destacam o potencial de implementação de D. davidsoni no manejo integrado para B. tabaci MEAM1 e justificam a neces-sidade de novos estudos em casas de vegetação e em campo.