Influence of Temperature and Relative Humidity on the Insecticidal Efficacy of Metarhizium anisopliae against Larvae of Ephestia kuehniella (Lepidoptera: Pyralidae) on Wheat.

A series of laboratory bioassays were conducted for the evaluation of the insecticidal efficacy of an isolate of Metarhizium anisopliae (Metschnikoff) Sorokin (Ascomycota: Hypocreales) against larvae of the Mediterranean flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), under various temperature-relative humidity (r.h.) conditions. The fungus was applied at four doses (0, 8 × 106, 8 × 108, and 8 × 1010 conidia ml-1) on wheat and insect mortality was assessed after exposure of 1, 2, 7, and 14 d. Bioassays were conducted at three temperatures (20, 25, and 30 °C) and two r.h. levels (55 and 75%). Although complete control was not achieved in any case, the fungus provided a considerable level of insect control. Mortality of E. kuehniella larvae on wheat treated with M. anisopliae ranged between 41.1 and 93.3% after 14 d of exposure, whereas the respective mortality levels in control dishes never exceeded 28.3%. The increase of temperature resulted in most cases to higher efficacy, indicating that temperature is an important factor for the performance of the fungus. In contrast, in most cases r.h. did not significantly affect the efficacy of the fungus, at least for the humidity levels tested.

The volatile oils from the oleo-gum-resins of Ferula assa-foetida and Ferula gummosa: A comprehensive investigation of their insecticidal activity and eco-toxicological effects.

Since time immemorial, the oleo-gum-resins of Ferula assa-foetida and F. gummosa are used in the traditional medical systems as well as in foodstuffs, perfumery and cosmetics. In the present study, we explored the insecticidal efficacy of the essential oils obtained from these oleo-gum-resins to widen their fields of industrial applications. The two essential oils were mainly composed of sulfides [sec-butyl (Z)-propenyl disulfide, sec-butyl (E)-propenyl disulfide, sec-butyl (Z)-propenyl trisulfide and sec-butyl (E)-propenyl trisulfide)] and monoterpenes (α-pinene, ß-pinene and ß-phellandrene), respectively, as determined by GC-MS analysis. The two essential oils were assayed for toxicity on a panel of insects, represented by species of public health relevance (Culex quinquefasciatus and Musca domestica), agricultural (Spodoptera littoralis) and stored-product pests (Prostephanus truncatus and Trogoderma granarium). The ecotoxicological effects of the essential oils were assessed on the aquatic microcrustacean Daphnia magna and the earthworm Eisenia fetida, as well as on human cells. Overall, the two essential oils were effective against important insect pests and vectors. On the other hand, they resulted cytotoxic to fibroblasts and non-target aquatic microcrustaceans. Thus, further insights are needed to determine the full spectrum of their eco-toxicological effects.

Effectiveness of eight essential oils against two key stored-product beetles, Prostephanus truncatus (Horn) and Trogoderma granarium Everts.

The use of chemical pesticides to preserve food commodities is a global issue of concern due to their negative effect on the environment and public health. In recent years, the European Union is trying to reduce their use, favoring alternative or complementary approaches based on natural products. In this scenario, plant-borne essential oils (EOs) represent valid options for Integrated Pest Management (IPM) programs. In the present study, the insecticidal effect of eight EOs obtained from plants from different parts of the world, namely Mentha longifolia, Dysphania ambrosioides, Carlina acaulis, Trachyspermum ammi, Pimpinella anisum, Origanum syriacum, Cannabis sativa and Hazomalania voyronii, were evaluated against two stored-product insect species of economic importance, Prostephanus truncatus and Trogoderma granarium. Simulating a small-scale stored-product conservation environment, an AG-4 airbrush was used to spray maize and wheat with 500 and 1000 ppm of EOs, then T. granarium and P. truncatus were exposed to the stored products and mortality was evaluated over selected time intervals (4, 8, and 16 h, and 1, 2, 3, 4, 5, 6, and 7 days). The EO of C. acaulis exhibited high efficacy against P. truncatus adults at both tested concentrations by killing > 97% of the individuals exposed to treated maize within 3 days at 500 ppm. The EO of D. ambrosioides eliminated all T. granarium adults exposed to 1000 ppm-treated wheat 2 days post-exposure. At this exposure interval, 91.1% of the exposed T. granarium adults died on wheat treated with 1000 ppm of C. acaulis EO. The EO of M. longifolia at both tested concentrations was the most effective against T. granarium larvae, leading to 97.8% mortality at 500 ppm after 3 days of exposure, and 100% mortality at 1000 pm 2 days post-exposure. At 1000 ppm, the EOs of D. ambrosioides and P. anisum led to 95.6 and 90% mortality, respectively, to larvae exposed to treated wheat for 7 days. Overall, our research shed light on the potential of selected EOs, with special reference to M. longifolia, D. ambrosioides, C. acaulis and P. anisum, which could be considered further to develop effective and alternative grain protectants to manage P. truncatus and T. granarium infestations.

Evaluation of Mating Disruption For the Control of Thaumetopoea pityocampa (Lepidoptera: Thaumetopoeidae) in Suburban Recreational Areas in Italy and Greece.

Thaumetopoea pityocampa (Denis and Schiffermüller) is a severe defoliator of various species of Pinus and Cedrus, while the urticanting hairs produced by its larvae cause public health problems for humans and pets. In the present study, we report results of trials (from summer 2015 until winter 2017) of mating disruption for management of T. pityocampa in different areas of Italy and Greece. Overall, the total number of male moths captured in mating disruption-treated plots over each season (70) was significantly lower than the respective number in untreated plots (780). The total number of winter nests was likewise significantly less in the mating disruption plots (13) compared with control plots (147). Our results indicate that mating disruption can be an important tool for judicious, insecticide-free control of T. pityocampa in urban, suburban, and recreational areas, where many alternative control measures are not available.

Management of the Pine Processionary Moth, Thaumetopoea pityocampa (Lepidoptera: Thaumetopoeidae), in Urban and Suburban Areas: Trials With Trunk Barrier and Adhesive Barrier Trap Devices.

In urban and suburban areas larvae of the pine processionary moth, Thaumetopoea pityocampa (Denis and Schiffermüller), cause serious defoliation to Cedrus, Pinus, and Pseudotsuga trees and health problems to humans and domestic or farm animals by their urticating setae. In this study, we present the results of biennial trials (2015-2016) on the management of T. pityocampa infestations using commercial or LIFE-PISA prototype trunk barrier and adhesive trap devices in Greece (Attica and Volos), Spain (Valencia), and Italy (Molise). In Attica, for both 2015 and 2016, the commercial trunk barrier trap devices captured significantly more T. pityocampa wintering migrant larvae compared to the adhesive barrier trap devices, indicating their high capture capacity. The total performance of the trunk barriers trap devices was 99.8% in 2015 and 99.6% in 2016. In Volos and Valencia, no significant differences were recorded between captures in commercial and LIFE-PISA prototype trunk barrier trap devices. In the tests that were conducted in Molise, the commercial trunk barrier trap devices exhibited high effectiveness in capturing the wintering migrant larvae during their procession, before they reach the ground for pupation. Moreover, significantly fewer male adults were captured by pheromone trap devices during summer 2016 in comparison with 2015 in the experimental area. Similarly, significantly fewer nests were formed on the experimental area trees in winter 2016 and 2017 compared with 2015. Our results show the potential of the trunk barrier trap devices in the management of T. pityocampa numbers after long-term application in urban and suburban areas.

Effect of two azadirachtin formulations against adults of Sitophilus oryzae and Tribolium confusum on different grain commodities.

The insecticidal effect of two azadirachtin-based insecticides, NeemAzal-T/S and Oikos 32 EC, was examined against adults of the grain beetles Sitophilus oryzae and Tribolium confusum on wheat and maize under different temperature and humidity regimes. The insecticides were applied at three dosages, equivalent to 50, 100, and 200 mg of active ingredient per kg of grain. Adults of the above species were exposed to the treated grains at 20, 25, and 30 degrees C and two relative humidity levels (55 and 75%), and mortality was assessed after 14 days of exposure. All adults were then removed, and the treated substrate remained under the same conditions for 45 more days. After this period, the grains were checked for progeny production. In both species and both commodities, mortality increased with insecticide dosage. For many dosage-formulation combinations, mortality increased with temperature at 55% relative humidity but the reverse was observed at 75% relative humidity. Comparing the two formulations, NeemAzal-T/S was more effective than Oikos 32 EC at all the combinations tested. NeemAzal-T/S was more effective at high relative humidity, but the efficacy of Oikos 32 EC was not much affected by the relative humidity. Survival was high, even at the higher dosages, in some of the temperature-humidity combinations. Progeny production of S. oryzae in the treated grains was considerably higher than that of T. confusum. The results of the present study indicate that further dosage increases and longer exposure times are needed to obtain a complete (100%) adult mortality in all combinations tested. However, the feasibility of using higher azadirachtin dosages (>200 mg/kg grain) is questionable for cost reasons. Consequently, the use of these substances is not comparable to the use of traditional grain protectants, which are usually used at dosages of <5 mg/kg grain. Although azadirachtin-based insecticides can be used with success for protection of stored grain, our study demonstrated that under certain circumstances such an application may not be effective. Abiotic factors (formulation, temperature, and relative humidity) had a more serious impact on the efficacy of these insecticides than did biotic factors (target species and commodity).

Insecticidal effect of NeemAzal against three stored-product beetle species on rye and oats.

The insecticidal effect of the azadirachtin-based insecticide, NeemAzal, was examined against adults of Rhyzopertha dominica (F.), Sitophilus oryzae (L.), and Tribolium confusum Jacquelin du Val in rye, whole oats, and peeled oats. The insecticide was applied at three dose rates, which were equivalent to 50, 100, and 200 ppm of azadirachtin A. Adults of the above-mentioned species were exposed to the treated grains at 25 degrees C and 65% RH, and mortality was assessed after 24 h, 48 h, 7 d, and 14 d of exposure. Then, all adults were removed, and the treated substrate remained at the same conditions for an additional 45 d. After this interval, the grains were checked for progeny production. In all species and commodities tested, mortality increased with the increase of dose and exposure interval, except for T. confusum on whole and peeled oats. For R. dominica, NeemAzal was more effective on oats than on rye and peeled oats. In contrast, at rates > or = 100 ppm, azadirachtin was equally effective against S. oryzae on whole rye and oats, where mortality was 100% after 7 and 14 d of exposure, respectively. NeemAzal was not very effective against T. confusum where adult mortality was low, even after 14 d of exposure at the highest rate. For all species, significantly less progeny were recorded in the treated grains than in the untreated grains, with the exception of T. confusum on oats where offspring was significantly reduced only at the highest rate.

Evaluation of the entomopathogenic fungi Beauveria bassiana, Metarhizium anisopliae, and Isaria fumosorosea for control of Sitophilus oryzae.

The entomopathogenic fungi Beauveria bassiana, Metarhizium anisopliae, and Isaria fumosorosea were tested against the stored-grain pest Sitophilus oryzae. The fungi were isolated from the soil (from three locations in Attica, Greece: B. bassiana from Tatoion, M. anisopliae from Marathon, and I. fumosorosea from Aghios Stefanos) using larvae of Galleria mellonella as bait. Suspensions of 2.11 × 10(7) and 2.11 × 10(8), 1.77 × 10(7) and 1.77 × 10(8), and 1.81 × 10(7) and 1.81 × 10(8) conidia per ml of B. bassiana, M. anisopliae, and I. fumosorosea, respectively, were applied by three treatments: (i) sprayed on food and set in petri dishes with adults of S. oryzae, (ii) sprayed on adults of S. oryzae and set in petri dishes without food, and (iii) sprayed on adults of S. oryzae and set in petri dishes with food. The observed mortality of S. oryzae adults during the overall exposure period for the lowest, as well as for the highest, concentrations of B. bassiana, M. anisopliae, and I. fumosorosea ranged from 0 to 100%. Concentration was, in most of the cases tested, a critical parameter that determined the "speed of kill" of the exposed insect species for B. bassiana and M. anisopliae. Conversely, concentration was not that critical for I. fumosorosea, and survival was high in some of the combinations tested, even after 14 days of exposure. Both in the highest and the lowest concentrations of fungi, the mortality of S. oryzae adults was higher when the fungi were applied on adults than when they were applied on food. Higher mortality was observed when food was absent than when food was present, in most of the cases tested. The high efficacy levels recorded in the current study indicate that the tested fungi could be effective biocontrol agents against S. oryzae.