Offering honey containing a selective insecticide as food for pests and parasitoids: another effective use

We investigated the effects of the presence of a selective insecticide, pyridalyl, in aqueous solutions of honey as food for adults of diamondback moth (DBM) Plutella xylostella (L.) and its larval parasitoid Cotesia vestalis (Halliday) on their performances. We used a commercial formulation of pyridalyl which contained 10% pyridalyl. Survival times of DBMs reared with honey solution with pyridalyl at 10 000‐fold dilution were not significantly different from those of DBMs reared with pure honey solution. However, at 1000‐fold and 100‐fold dilutions of pyridalyl in honey solution, survival times were significantly shorter than those with honey solution alone. By contrast, survival times of C. vestalis reared with honey solution with pyridalyl at 1000‐fold and 100‐fold dilution were not significantly different from those of C. vestalis reared with pure honey solution. Offering honey solution with pyridalyl at 100‐fold dilution to C. vestalis did not affect its parasitization ability or offspring sex ratio. The novel aspects of the use of selective pesticides to control DBMs using C. vestalis are discussed.     

Influence of cabbage resistance and colour upon the diamondback moth and its parasitoid Oomyzus sokolowskii

Host plant resistance and biological control are vital integrated pest management tools against the diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), but to date no study has investigated this system including the DBM parasitoid Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae). We examined oviposition and development of P. xylostella exposed to two commercial cabbage cultivars (green ‘Chato de quintal’ and red ‘Roxo’) and possible effects upon O. sokolowskii. Under free‐choice tests, DBM females laid significantly more eggs on plants of the green cabbage, even though several population growth parameters showed that DBM developed better on the red cabbage. Furthermore, a laboratory free‐choice test with artificially green‐ and red‐painted kale leaf discs demonstrated a similar oviposition preference pattern, with green colour being preferred over red colour. The preference was apparently visually mediated; olfactometer tests showed similar attraction of moths to both green and red cultivars in choice and non‐choice tests. Host plant cultivar had no statistically significant effect on female parasitoid behaviour towards DBM larvae, nor on parasitoid numbers or longevity. Moreover, wasps parasitizing DBM larvae reared on the green cultivar developed more quickly and in larger numbers per parasitized larva. Thus, feeding on green cabbage rather than red does not hinder, and potentially even enhances, control of DBM by O. sokolowskii. On a practical level, these results suggest that intercalating green cabbage cultivars as a trap crop might help protect more profitable red cultivars in growing fields.     

Laboratory evaluation of predation rates of two native natural enemies on the exotic pest Bagrada hilaris

Laboratory studies were conducted to determine the consumption rates of two native predators found attacking the exotic invasive stink bug Bagrada hilaris (Burmeister) (Hempitera: Pentatomidae) in field plots in New Mexico, USA. Individual field‐collected adults of the spined soldier bug, Podisus maculiventris (Say) (Hempitera: Pentatomidae) and the soft‐winged flower beetle, Collops vittatus (Say) (Coleoptera: Melyridae), were provided daily with fixed numbers of different life stages of B. hilaris under controlled conditions. Consumption rates were recorded daily for ten consecutive days for a total of 20 adult P. maculiventris and 20 adult C. vittatus per prey life stage. For P. maculiventris, predation rates were obtained in relation to adult, third and fifth instar prey, and for C. vittatus for first, second and third instar prey. On average, predation on third and fifth instar B. hilaris nymphs by P. maculiventris was 0.6 ± 0.1 and 0.9 ± 0.1 per day respectively. Predation rates on adults were slightly higher (1.3 ± 0.1 per day), with female prey being consumed at a significantly higher rate than male prey when three mating pairs of B. hilaris were provided per day (0.8 ± 0.1 females per day vs. 0.5 ± 0.1 males per day). Collops vittatus adults provisioned daily with 20 first instar B. hilaris nymphs killed a mean total of 4.7 ± 0.4 and 9.3 ± 0.6 prey each day (for male and female beetles respectively), with only approximately half that number of prey being fully consumed. Partial consumption of prey by this species was also observed with second and third instar nymphs, but to a lesser degree. Female beetles consumed significantly more prey than did male beetles when fed first and third instar B. hilaris, but not when given second instar prey.     

Current status of the management of fall webworm,Hyphantria cunea: Towards the integrated pest management development

The fall‐webworm (FWW), Hyphantria cunea, is a highly polyphagous insect pest that is native to North America and distributed in different countries around the world. To manage this insect pest, various control methods have been independently evaluated in the invaded areas. Some of the control methods have been limited to the laboratory and need further study to verify their effectiveness in the field. On the other hand, currently, integrated pest management (IPM) has become a promising ecofriendly insect pest management option to reduce the adverse effect of insecticides on the environment. The development of an IPM for an insect pest must combine different management options in a compatible and applicable manner. In the native areas of the insect pests, there are some recommended management options. However, to date, there is no IPM for the management of the FWW in the newly invaded areas. Therefore, to develop an IPM for this insect pest, compilation of effective management option information is the first step. Thus, believing in the contribution of an IPM to the established management strategies, the chemical, biological, natural enemy, sex pheromone, and molecular studies regarding this insect were reviewed and potential future research areas were delineated in this review study. Therefore, using the currently existing management options, IPM development for this insect pest should be the subject of future research in the newly invaded areas.     

Utilisation of plant functional diversity in wildflower strips for the delivery of multiple agroecosystem services

Increased plant diversity in cropping systems can play an important role in agriculture by enhancing arthropod‐mediated ecosystem services, including biological control and pollination. However, there is limited research investigating the concurrent influence of plant functional diversity within cultivated systems on different arthropod functional groups, the provision of multiple ecosystem services, and crop yield. During a field experiment, repeated over 2 years, we measured the effect of increasing plant functional diversity on community structure of arthropod visitors, the abundance of multiple pests and induced crop damage, and fruit production in two varieties of tomato. Plant resources (floral and extra‐floral nectar and pollen) were included within experimental plots in four levels, with each level increasing the plant functional group richness, based on floral morphology and availability of resources, in a replacement series. The presence of sown flower mixtures in experimental plots was associated with increased abundance and diversity of natural enemy functional groups and an enhanced abundance of bees (Hymenoptera: Apiformes). However, we only detected relatively small variability in arthropod visitors among types of mixtures, and increased abundance of natural enemies did not translate into stronger pest suppression or reduced crop damage. Lepidoptera pest damage was significantly higher in plots adjacent to wildflower strips, an ecosystem disservice, but a significantly higher crop productivity was recorded from these plots. Our results provide evidence that inclusion of non‐crop plant resources in agroecosystems can improve the conservation of beneficial arthropods and may lead to increased crop productivity.