Spodoptera frugiperda (J.E. Smith, 1797) is considered a key pest of maize. However, the artificial diets used for rearing this insect in the laboratory do not contain corn. The aim of this study was to evaluate the biology and to compare the food consumption by S. frugiperda, as well as the food preference of the larvae in the standard diet and the corn-based diet. Three of the following diets were evaluated: a standard diet based on beans (D1), a diet with corn flour as substitute for wheat germ (D2), and a diet replacing beans with green corn (D3). The biological parameters evaluated were period and survival of larvae and pupae; weight of male and female pupae; sex ratio; fecundity; egg incubation period; and adult longevity. The nutritional indices were determined and the biological data obtained were used to determine the parameters of fertility life tables; we also performed a multiple-choice test (feeding test). Larval development of S. frugiperda occurred in all three diets, although without oviposition by females developed from larval fed on D2. There was no difference among the diets in relation to the fertility life table parameters. The diet D2 resulted in better ingestion, digestion, assimilation, and conversion of food, but was associated with a metabolic cost to assimilate the food. Using a multiple-choice test, we observed that the larvae preferred diet D2. Based on our results, the most adequate diets for rearing S. frugiperda in the laboratory are D1 and D3.

The objective of our work was to identify the prey that offers optimum production of the predator, Podisus nigrispinus (Dallas). The cost of predator production was determined for each prey. We test the hypothesis that prey types supporting optimal development do not facilitate cost-effective rearing of P. nigrispinus. Second-instar nymphs of P. nigrispinus were reared in 1000-ml transparent plastic containers and maintained under controlled conditions (temperature, 25 ± 1°C; photophase duration, 12 h; relative humidity, 70 ± 10%), and the following biological aspects were evaluated: nymph viability, length of the nymphal period, and weight of fifth-instar nymphs. The adults were isolated in pairs (one female and one male) in Petri dishes, and the following biological aspects were evaluated: lifespan, adult weight after emergence, number of eggs per female, egg mass in females, number of eggs per egg mass, durations of the pre-oviposition, oviposition, and post-oviposition periods, viability, and length of the embryonic period. On the basis of our results, we conclude that the prey that leads to optimal development of P. nigrispinus is the larvae of Diatraea saccharalis (Fabr.), and the most cost effective prey for rearing P. nigrispinus is the larvae of Musca domestica L.

The methodology recommended by IOBC/WPRS influenced results regarding the use of different species of parasitoids, and the use of a single parasitoid species in their experiment is questionable.

This study evaluated the predation by Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae) at various densities of larvae and pupae of the pest Plutella xylostella (L.) (Lepidoptera: Plutellidae). We tested predator behavior of female P. nigrispinus at six experimental densities (1, 5, 10, 15, 20, or 25 prey items in a 1‐l transparent plastic container, replicated 15 times for each density) of both the fourth instar and pupae of P. xylostella. The number of prey consumed was monitored every 15 min for 12 h and was subsequently monitored at 24 h. Podisus nigrispinus females were weighed before and after the experiments to determine the effect of different densities of prey on their weight gain. Female predators had a Type‐II functional response, with attack rate estimated at 1.387 and 0.260 and a handling time of 0.091 and 0.183 h−1 for larvae and pupae, respectively. Podisus nigrispinus consumed on average 10.9 larvae or 5.5 pupae in 24 h. Despite the similarity of the response type, P. nigrispinus preferred to feed on larvae, rather than on pupae.

The aim of this study was to assess the biological aspects and food preferences of Helicoverpa armigera fed different sunflower genotypes and an artificial diet. Tests were performed under multiple-choice and no-choice conditions to evaluate the biological characteristics of H. armigera. In addition, the biological data obtained were used to determine parameters of fertility life tables. The results showed that H. armigera does not have a feeding preference among the sunflower genotypes tested. The larval period on sunflower ranged from 15.0 to 16.2 days. The maximum fecundity on sunflower was 542.6 eggs/female and that on the artificial diet was 794.5 eggs/female. In general, insects feeding on Helio 250 consumed greater quantities of leaves, had higher survival until the end of the pupal stage, displayed high population growth rates, and had low population doubling times, suggesting that in the field populations will achieve greater population densities when fed on Helio 250. Insects that fed on CF101 consumed smaller leaf areas, had lower survival until the end of the pupal stage, lower fertility rates, and lower population growth rates, and may also have displayed lower population densities and smaller reductions in field productivity. This insect developed best on an artificial diet in comparison to sunflower genotypes studied.

Understanding the prédation on pest insects through controlled feeding on their prey can provide insight into natural methods of pest control. The growth, survival, and development of the predatory stink bug (Podisus nigrispinus Dallas) fed on the eggs, larvae, and pupae of the diamondback moth, Plutella xylostella L., was examined in the laboratory. Second instar P. nigrispinus (12-24 h old) were fed various prey and monitored daily as they molted through nymphal stages and adulthood until death. The growth, survival, and egg production of stink bugs fed P. xylostella larvae and pupae were compared. P. xylostella eggs and first instars are inadequate food sources, whereas fourth instars and pupae can sustain the development of P. nigrispinus. Egg output of females was greater with pupae than with larvae. Male longevity was greater with larvae than with pupae. More P. xylostella larvae than pupae were consumed by P. nigrispinus. The high consumption rates of P. xylostella by P. nigrispinus in the laboratory indicate that this predatory stink bug may be a potential biological control agent for this pest.KEY WORDS Asopinae, biological control, insect biology, predatory stink bug, Brassicaceae

Plutella xylostella (L.) is susceptible to both the entomopathogen Bacillus thuringiensis and the predator, Brazilian spined soldier bug [Podisus nigrispinus (Dallas)]. The objective of this study was to measure the interaction between the bacterium B. thuringiensis and the predator P. nigrispinus. We also studied the behavior of P. nigrispinus in relation to its choice between B. thuringiensis-infected and healthy P. xylostellais larvae. In the first treatment, P. nigrispinus nymphs were fed daily with B. thuringiensis-infected P. xylostella larvae and distilled water. In the second treatment, nymphs were fed daily with healthy larvae and a suspension of B. thuringiensis as a source of water. The control nymphs were fed daily with healthy larvae and water. Adult P. nigrispinus were separated by sex, couples were formed, and they were fed daily with P. xylostella larvae derived from the treatments. We followed the development of P. nigrispinus and measured its biological characteristics. On the basis of these data, parameters were determined for the construction of life tables. A choice test was used to compare infected and healthy larvae. The HD1 strain of B. thuringiensis does not affect the biological characteristics of P. nigrispinus when fed infected larvae and water or healthy larvae and B. thuringiensis suspension. Our study shows that integrated management of P. xylostella, a pest of the Brassicaceae, is feasible by using the HD1 strain of B. thuringiensis and the predator P. nigrispinus, because the predator shows no preference for infected or healthy P. xylostella larvae.

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