Brown marmorated stink bug, Halyomorpha halys Stål, is an invasive species of Asian origin that is an important agricultural pest in the eastern United States. Sentinel egg masses are tools used to ...assess the impact of natural enemies on H. halys populations. To determine the effect of host egg age and storage conditions on their susceptibility to parasitism, H. halys eggs were stored at different temperatures for different lengths of time and then exposed to Anastatus reduvii (Howard), a native natural enemy of H. halys occurring in eastern North America. For eggs stored at 15, 20, and 25°C and then exposed to A. reduvii, the number of host eggs from which parasitoid offspring emerged declined with age of eggs. Control eggs (exposed to parasitoids without being stored) and those eggs stored for only 5.5 degree-days (DD) (=0.5 days) at 25°C yielded the highest percentage of parasitoids at 88.2 and 88.3%, respectively. For eggs stored at 20 and 25°C for 7.3 DD to about 36 DD, offspring emerged from about 58 to 73% of eggs, and total parasitism (emerged + unemerged parasitoids) ranged from about 70 to 80%. Parasitoid emergence was significantly lower for host eggs stored at 15°C for comparable times at 20 and 25°C. Stink bugs nymphs hatched from <0.6% of all eggs. Parasitoid-induced host egg abortion was an important component of egg mortality caused by A. reduvii, with underdeveloped stink bug nymphs, undifferentiated cell contents, and parasitoid host feeding occurring across all storage treatments.
Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a serious threat to tomato (Solanum lycopersicum L.) crops in South America. In Europe, after its first detection in Spain in 2006, it rapidly ...spread through the Mediterranean basin, reaching Italy 2 yr later. The aim of our work was to find indigenous effective biological control agents and to evaluate their potential role in the control of larval populations of T. absoluta in controlled conditions. Nine species of larval parasitoids emerged from field-collected tomato leaves infested by T. absoluta. The most abundant, Necremnus near artynes (Walker) and Necremnus near tidius (Walker) (Hymenoptera:Eulophidae), were tested in laboratory parasitism trials. Furthermore, because the species N. artynes and N. tidius are each reported in literature as an ectoparasitoid of Cosmopterix pulchrimella Chambers (Lepidoptera: Cosmopterigidae) on upright pellitory plants, olfactometer bioassays were performed to assess the response of our parasitoids to the odors of tomato and pellitory leaves infested by T. absoluta and C. pulchrimella, respectively, compared with healthy ones. Both Necremnus species showed good adaptation to the invasive pest, and we observed a high larval mortality of T. absoluta because of host feeding and parasitism. Even olfactory responses highlighted a preference of both wasps for tomato plants infested by the exotic pest. These preliminary results demonstrated a high suitability of these indigenous natural enemies for controlling T. absoluta. Further investigations are needed to confirm their role as potential biological agents in commercial tomato plantations.
Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) is an important parasitoid of the potato psyllid, Bactericera cockerelli Sulc (Hemiptera: Triozidae). We quantified the biology and life table ...parameters of T. triozae parasitizing B. cockerelli nymphs under laboratory conditions (26 ± 2 °C, 60 ± 10 % RH and 14:10 L:D h). Parasitoid developmental times were 1.5, 3.5, 5.7 days for eggs, larvae and pupae respectively, with an average of 12.0 days from egg to adult emergence. Female pupae took 0.4 day longer to develop than male pupae. Adult females lived 19.9 ± 4.5 days and had a 1.9 ± 0.8 days preoviposition period. Each female laid an average of 165.4 ± 45.2 eggs during her lifetime. The net reproductive rate (R ₀), generation time (T), intrinsic rate of increase (r ₘ), doubling time (DT) and the finite rate of increase (λ) were 130.9, 18.72, 0.26, 2.7, and 1.3 respectively. The potential for the use of T. triozae as a biological control agent of B. cockerelli is discussed.
Our study focused on a predaceous species in one of the most diverse, but poorly investigated Neotropical lacewing genera:
Chrysopodes. Members of this genus have several traits that characterize ...valuable natural enemies and studies of their life histories are needed to assess their potential usefulness in biological control. In outdoor rearings in southeastern Brazil,
Chrysopodes (
Chrysopodes)
lineafrons Adams and Penny underwent development and reproduction without interruption or dormancy; it produced eight full generations in slightly more than one year (375 days). Under a series of constant temperatures between 28.5 and 18
°C, the life cycle (oviposition—adult emergence) ranged from 27 to 64 days, whereas a constant temperature slightly below 15
°C prevented development. Developmental rates were linearly related to temperature; preimaginal development was completed within 470 degree-days above a lower thermal threshold of 10.7
°C; the rates of development under fluctuating temperatures outdoors closely reflected the developmental responses to constant temperatures indoors. Reproductive performance appeared highest at 25
°C; at this temperature, females oviposited 10 days after emergence, at a rate of ∼9 eggs per day, for a total of ∼200 eggs per individual. A comparison of
Ch. (
Ch.)
lineafrons with other green lacewing species indicated that this predator has potential as a native natural enemy in Neotropical orchards and may be readily amenable to continuous mass-rearing.
Hydrometra procera is one of the semi-aquatic bugs found in paddy fields. I investigated the population fluctuation and food habits of the species to evaluate its potential as a biological control ...agent against Sogatella furcifera, Nilaparvata lugens, and Nephotettix cincticeps in a paddy field under sustainable cultivation. Through the present study, arthropods belonging to the following 7 taxa were sucked by the bug; Onychiuridae gen. sp., S. furcifera, N. lugens, N. cincticeps, Chironomidae gen. sp., Brachycera gen. sp. and Theridiidae gen. sp. Population density of the bug in the paddy field showed two peaks a year, in late June and in September. The former peak tended to synchronize with a peak of S. furcifera nymphs, while the latter peak with N. lugens, N. cincticeps, and collembolans. Therefore, main food resource of the bug should be these insects in the paddy field. Ovarian development of the bug under field condition revealed that the bug could be univoltine since females possessing mature ovary appeared once a year, from June to July. Rearing tests in laboratory at 22, 27 and 31℃ showed a developmental zero (T0) of 14.0℃ with a thermal constant (K) of 250℃-day from egg to adult for the bug, H. procera.
We investigated the predatory ability of Carabus yaconinus (Coleoptera: Carabidae) on larvae of Spodoptera litura (Lepidoptera: Noctuidae) in the laboratory. A C. yaconinus adult preyed on ca. 90 S. ...litura larvae at the second-instar stage during 24 h. The number of larvae killed in 24 h decreased to ca. 40, 30 and 20 at third-, fourth- and fifth-instar stages, respectively. The wet weight of S. litura larvae killed by a C. yaconinus in 24 h increased with the larval stages of S. litura, and was highest for the fifth-instar stage. C. yaconinus adults occasionally left the predation unfinished and bit another live prey. The proportion of half-eaten prey varied with the larval stage of the prey. C. yaconinus can efficiently kill large numbers of S. litura larvae; thus, it may play an important role as a natural enemy of lepidopteran pests in agricultural fields.
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