Pre-exposure to sex pheromone did not affect mating behavior in the sweetpotato weevil <Emphasis Type="Italic">Cylas formicarius</Emphasis>

In sterile insect technique (SIT) programs, the released sterile males are important for their effectiveness. The use of sex pheromones to collect males is economical; however, pre-exposure to sex pheromones may affect male mating behavior, and would thus reduce the effectiveness of the SIT programs. Males exposed to sex pheromone may become attractive to other males due to pheromone adsorption on their body impregnation, prevent mating and reduce the dispersal of sterile males. We examined the effect of pre-exposure to sex pheromone on the mating behavior of male sweetpotato weevil Cylas formicarius. Pre-exposure to high-dose sex pheromone for 24 h did not affect the male mating behavior of C. formicarius, and the exposed males did not attract other males. These results suggest that male C. formicarius that were collected from a mass-rearing facility using sex pheromone can be effectively used in SIT programs.     

Evaluation of aerosol devices for simultaneous disruption of sex pheromone communication in <Emphasis Type="Italic">Cydia pomonella</Emphasis> and <Emphasis Type="Italic">Grapholita molesta</Emphasis> (Lepidoptera: Tortricidae)

A two-year study was conducted evaluating Puffer^® aerosol dispensers (Suterra LLC, Bend, OR, USA) for mating disruption of codling moth, Cydia pomonella (L.), and the oriental fruit moth, Grapholita molesta (Busck). The Puffer^® dispenser consists of a pressurized metal canister loaded with pheromone active ingredients dissolved in solvent and housed within a circuit-controlled, plastic dispensing cabinet programmed to release an aerosol spray of pheromone at regular intervals. Puffers^® were deployed at the label-recommended rate of 2.5 ha^?1 and released ca. 5–10 mg of pheromone (depending on treatment) per 15 min during a 12-h cycle beginning each day at 15:00 h for the duration of the season. In 2005, commercially-managed apple plots (3.2–4.9 ha) were treated with Puffers^® releasing both species’ pheromone simultaneously (dual-species) or with twice the number of adjacently-deployed Puffers^® (4–6 m apart) releasing each individual species’ pheromones (single-species), while maintaining comparable overall release rates of pheromone between these two treatments. Plots 100 m away and not treated with pheromone served as the control. Disruption of male C. pomonella and G. molesta orientation to pheromone-baited traps was 46–75 and 91–98%, respectively, in Puffer^®-treated plots compared with untreated controls. There was no statistical difference in moth disruption between plots treated with dual-species and single-species Puffers^®. Fruit injury was not statistically different between Puffer^®-treated plots and control plots not receiving pheromone. In 2006, disruption of male moth orientation to traps was 24–26 and 84–97% in Puffer^®-treated plots (2.9–5.7 ha) for C. pomonella and G. molesta, respectively, compared with untreated controls. During this season, fruit injury was lower in pheromone-treated plots compared with untreated controls at mid-season, but not at pre-harvest. Combining the pheromone of both species into single Puffer^® units did not decrease efficacy of disruption compared with deploying twice as many Puffers^® releasing a similar amount of each individual species’ pheromone suggesting that multi-species disruption using Puffers^® is a viable option. However, we conclude that the efficacy of disruption attained with low-densities (2.5 ha^?1) of Puffers^® at the moth densities recorded in this study is insufficient for effective control of C. pomonella without input of companion insecticides.     

Effectiveness of Neem (<Emphasis Type="Italic">Azadirachta indica</Emphasis>) insecticides against Brassica pod midge (<Emphasis Type="Italic">Dasineura brassicae</Emphasis> Winn<Emphasis Type="Italic">.</Emphasis>)

The efficiency of the botanical insecticide (BI) NeemAzal T/S (containing 1% Azadirachtin A), on the basis of azadirachtin applied in a dose of 20 g a.i. ha⁻¹ against Brassica pod midge (Dasineura brassicae), has been monitored for 4 years. The biological efficiency of BI was compared with the efficiency of some synthetic insecticides. It was ascertained that BI was very efficient in decreasing the number of damaged oilseed rape pods (ranging from 56.5 to 85.9% compared to untreated plants) and its efficiency was comparable with synthetic insecticides based on Chloronicotinyl (Thiacloprid) and Neonicotinoid (Acetamiprid). BI’s efficiency was, in some years, even significantly higher compared to pyrethroid (λ-cyhalothrin). The high biological efficiency of azadirachtin that we ascertained was significantly reflected in increasing potential crop yields. The yield increase of azadirachtin ranged between 9.3 and 19.4% compared to the control sample. Azadirachtin showed the highest yield for the whole time of experimentation, and in some years the yield increase was significantly higher compared to some synthetic agents.     

Successful <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation of <Emphasis Type="Italic">Populus tomentosa</Emphasis> with apple <Emphasis Type="Italic">SPDS</Emphasis> gene

The problem of salinized soils has become one of the most serious constraints to agricultural and forest productivity. With the purpose of enhancing salt stress tolerance of Populus tomentosa, we transformed this tree species with spermidine synthase （SPDS） genes derived from an apple by an Agrobacterium-mediated method. Four transgenic clones were confu＇med by PCR and Southern blot analysis. As well, the expression of introduced SPDS genes was analyzed by real-time quantitative PCR.     

Effects of <Emphasis Type="Italic">Eucalypt</Emphasis> and <Emphasis Type="Italic">Acacia</Emphasis> plantations on soil water in Sumatra

Indonesia’s pulp and paper industry needs a large area of sustainably grown plantations to support its continued development. Acacia mangium has been the key species underpinning the pulp and paper industries in Sumatra, however increased disease pressure on A. mangium is expected to require large-scale conversion of Acacia plantations to Eucalyptus in the near future. The effect of such a large scale change in plantation species on soil moisture, for both tree production, and catchment hydrology is unknown. In this study we sought to characterize the impacts of plantation species (Acacia or Eucalyptus) and nitrogen management, on soil moisture, soil water depletion and depth to groundwater under stands of Acacia mangium and Eucalyptus pellita over the first 2–3 years after establishment. The study was conducted in experiments at four sites in Sumatra, Indonesia. Soil moisture and soil water depletion were not influenced by plantation species or fertilizer treatment. Soil moisture content and soil water depletion were strongly influenced by shallow groundwater at two of the four sites, however depth to groundwater did not influence stem growth. Results from the field trials cautiously suggest that large scale conversion of Acacia mangium to Eucalypt species in these regions is unlikely to result in increased moisture stress, nor is conversion of plantation species likely to lead to substantial differences in catchment hydrology. This study demonstrated the importance of conducting multi-site studies when investigating biophysical relationships in forest/plantation systems.     

Insecticidal properties of <Emphasis Type="Italic">Thymus persicus</Emphasis> essential oil against <Emphasis Type="Italic">Tribolium castaneum</Emphasis> and <Emphasis Type="Italic">Sitophilus oryzae</Emphasis>

Red flour beetle Tribolium castaneum (Herbst) and rice weevil Sitophilus oryzae (L.) are considered to be the major insect pests in storage. Essential oils from aromatic plants are recognized as proper alternatives to fumigants. Thymus persicus (Ronniger ex Rech. f.) is one of these plants that have medicinal properties and is indigenous to Iran. The essential oil was obtained from aerial parts of the plant and analyzed by GC and GC–MS. Carvacrol (44.69%) and thymol (11.05%) were the major constituents of the oil extracted. In this experiment, fumigant toxicity of the essential oil was studied against T. castaneum, S. oryzae at 27 ± 1°C and 60 ± 5% RH in dark condition. The adult insects were exposed to the concentrations of 51.9, 111.1, 207.4 and 370.4 μl/l air to estimate median lethal time (LT₅₀) values. The fumigant toxicity was increased in response to increased essential oil concentrations. The LT₅₀ values at the lowest and the highest concentrations tested were ranged from 28.09 to 13.47 h for T. castaneum, and 3.86 to 2.30 h for S. oryzae. It was found that S. oryzae adults were much more susceptible to the oil than T. castaneum. After 24 h of exposure, the LC₅₀ values (95% fiducial limit) for T. castaneum and S. oryzae were estimated to be 236.9 (186.27–292.81) and 3.34 (2.62–4.28) μl/l air, respectively. These results suggest that T. persicus essential oil merits further study as potential fumigant for the management of these stored-product insects.     

Toxicity of synthetic and biological insecticides against adults of the <Emphasis Type="Italic">Eucalyptus</Emphasis> snout-beetle <Emphasis Type="Italic">Gonipterus</Emphasis><Emphasis Type="Italic">scutellatus</Emphasis> Gyllenhal (Coleoptera: Curculionidae)

Toxicity by contact and by ingestion of lufenuron, flufenoxuron, lambda (λ)-cyhalothrin, cypermethrin, thiamethoxam and five entomopathogenic insecticides (three formulations of Beauveria bassiana, a compound containing spores of Metarhizium anisopliae var. acridum, and a mixture of Brevibacillus laterosporus, Bacillus licheniformis and Bacillus chitinosporus) were evaluated on adults of the Eucalyptus snout-beetle Gonipterus scutellatus Gyllenhal (Coleoptera: Curculionidae) under laboratory conditions. By contact, entomopathogenic fungus B. bassiana EC and the pyrethroid λ-cyhalothrin exhibited the highest efficiency, achieving 100 and 97.5% mortality, respectively. By ingestion, the highest mortality was obtained by B. bassiana EC (100%) and thiamethoxam (95%). Flufenoxuron and lufenuron, bacteria mixture and M. anisopliae showed a weak toxicity. Furthermore, we found a sex-biased mortality, being males more affected. Due to the good performance and low risk to humans and environment, B. bassiana EC (strain PPRI 5339) appears to be the most promising product to promote an IPM programme in South Africa.     

Challenges of pheromone-based mating disruption of <Emphasis Type="Italic">Cydia strobilella</Emphasis> and <Emphasis Type="Italic">Dioryctria abietella</Emphasis> in spruce seed orchards

Seed orchards function as the primary source of high-quality seeds for reforestation in many European countries, but their seed yields can be severely reduced due to seed- and cone-feeding insects. We evaluated various parameters of pheromone-based mating disruption for control of the moths Cydia strobilella and Dioryctria abietella, which are major pests in European Picea abies seed orchards. We applied different types of pheromone dispensers (rubber septa or wax droplets) at different densities and heights, and with different amounts of active components, covering whole orchards or part of an orchard. The efficacy of the treatment was evaluated by analysing male captures in pheromone-baited assessment traps, and presence of larvae in cones. A dramatic decrease (94–100%) in capture of males in traps occurred in all pheromone-treated plots compared to control plots for both moth species. In contrast, a subsequent reduction in larval numbers in cones was only achieved when wax droplets were used as the dispensing formulation at high density and at the highest pheromone dose tested, and only in half of the trials for each pest species. Electrophysiological recordings using antennae of male C. strobilella indicated elevated pheromone concentrations in a treated plot versus a control plot. Our results show that mating disruption has potential to reduce cone damage in spruce seed orchards caused by C. strobilella and D. abietella, but optimisation of the technique is required to achieve consistent and efficient population suppression of these pests.     

Management Effects on Biomass and Foliar Nutritive Value of <Emphasis Type="Italic">Robinia pseudoacacia</Emphasis> and <Emphasis Type="Italic">Gleditsia triacanthos</Emphasis> f. <Emphasis Type="Italic">inermis</Emphasis> in Arkansas,USA

The browse potential of black locust (Robinia pseudoacacia L.) and thornless honey locust [Gleditsia triacanthos f. inermis (L.) Zabel] has not been adequately tested. Our objective was to determine effects of fertilization and pollarding on biomass and foliar nutritive value in separate studies of black locust and thornless honey locust in Arkansas, USA. Shoots were sampled monthly for two consecutive growing seasons in 2002 and 2003 to determine foliar, shoot, and total aboveground biomass, shoot basal diameter, and foliar nutritive value (crude protein and in vitro digestibility). Black locust yielded more foliar biomass when pollarded at 50 or 100 cm and fertilized with 600 kg P ha⁻¹, than at 5 cm with or without P, averaging 3.5 Mg dry matter ha⁻¹. Black locust foliar crude protein and in vitro dry matter digestibility ( ≤ 170 and 534 g kg⁻¹, respectively) decreased as leaves aged, but still met maintenance needs for beef cattle (Bos taurus L.). Thornless honey locust had little agronomic potential because of slow establishment, low foliar yield (330 kg ha⁻¹), and a 2% reversion to undesirable thorny phenotype. Black locust should be considered for livestock browse when drought induces semi-dormancy of herbaceous forages.     

Bioremediation of CCA-treated wood by brown-rot fungi <Emphasis Type="Italic">Fomitopsis palustris</Emphasis>, <Emphasis Type="Italic">Coniophora puteana</Emphasis>, and <Emphasis Type="Italic">Laetiporus sulphureus</Emphasis>

This study evaluated oxalic acid accumulation and bioremediation of chromated copper arsenate (CCA)-treated wood by three brown-rot fungi Fomitopsis palustris, Coniophora puteana, and Laetiporus sulphureus. The fungi were first cultivated in a fermentation broth to accumulate oxalic acid. Bioremediation of CCA-treated wood was then carried out by leaching of heavy metals with oxalic acid over a 10-day fermentation period. Higher amounts of oxalic acid were produced by F. palustris and L. sulphureus compared with C. puteana. After 10-day fermentation, oxalic acid accumulation reached 4.2 g/l and 3.2 g/l for these fungi, respectively. Fomitopsis palustris and L. sulphureus exposed to CCA-treated sawdust for 10 days showed a decrease in arsenic of 100% and 85%, respectively; however, C. puteana remediation removed only 18% arsenic from CCA-treated sawdust. Likewise, chromium removal in F. palustris and L. sulphureus remediation processes was higher than those for C. puteana. This was attributed to low oxalic acid accumulation. These results suggest that F. palustris and L. sulphureus remediation processes can remove inorganic metal compounds via oxalic acid production by increasing the acidity of the substrate and increasing the solubility of the metals.An erratum to this article can be found at     

Enzymatic saccharification and ethanol production of <Emphasis Type="Italic">Acacia mangium</Emphasis> and <Emphasis Type="Italic">Paraserianthes falcataria</Emphasis> wood,and <Emphasis Type="Italic">Elaeis guineensis</Emphasis> trunk

We examined the saccharification and fermentation of meals from Acacia mangium wood, Paraserianthes falcataria wood, and Elaeis guineensis trunk. The levels of enzymatic hydrolysis of cellulose and ethanol production were highest for P. falcataria wood and lowest for A. mangium wood. Ultrasonication pretreatment of meal further increased the rates of hydrolysis and ethanol production in meal from P. falcataria wood. Through this pretreatment, hemicelluloses (xylan and xyloglucan) and cellulose were released in the meal from P. falcataria wood. Loosening of hemicellulose associations can be expected to make P. falcataria wood more useful for bioethanol production.     

Aboveground biomass equations for individual trees of <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>, <Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis> and <Emphasis Type="Italic">Larix kaempferi</Emphasis> in Japan

Generic equations are proposed for stem, branch and foliage biomass of individual trees in even-aged pure stands of Cryptomeria japonica, Chamaecyparis obtusa and Larix kaempferi. Biomass data was collected from a total of 1,016 individual trees from 247 stands throughout Japan, and five regression models were assessed by root mean square error, mean bias, fit index (FI), and AIC. The results show that a power equation using diameter at breast height (dbh) and height is the most suitable for all species and components. This equation is more accurate than the familiar power equation that uses ‘dbh² height’, and it expresses the greater volume of branch and foliage mass of trees with a lower height/diameter ratio. A power equation using dbh is more reasonable for models with dbh as the only independent variable and more accurate than a power equation using ‘dbh² height’ for estimating branch and foliage mass. Estimating error for branch and foliage mass is larger than that for stem mass, but the entire aboveground biomass can be estimated with an error of less than 19%, except in the case of small trees with dbh less than 10 cm.     

Side effects of selected insecticides on the <Emphasis Type="Italic">Tuta absoluta</Emphasis> (Lepidoptera: Gelechiidae) predators <Emphasis Type="Italic">Macrolophus pygmaeus</Emphasis> and <Emphasis Type="Italic">Nesidiocoris tenuis</Emphasis> (Hemiptera: Miridae)

Tuta absoluta is a pest native to South America that produces significant damage to tomato crops and was first detected in Europe in late 2006. Data obtained during 2008 from commercial tomato crops in which IPM was applied suggested that good pest control was possible through the combined action of the predatory mirid bugs Macrolophus pygmaeus and Nesidiocoris tenuis and the use of selective insecticides. The aim of our study was to evaluate the lethal and sublethal side effects of three of the insecticides most widely used to control T. absoluta on these predators: azadirachtin, spinosad and indoxacarb. Seven days after applying the treatment at the maximum recommended field rates, the mortality produced by indoxacarb ranged from 28% for nymphs of M. pygmaeus to 77% for females of N. tenuis and were significantly higher than those produced by azadirachtin, spinosad and the control (<13%). However, indoxacarb did not affect the number of descendants of females exposed to residues during the last days of their preimaginal development. In contrast, spinosad significantly reduced the offspring of M. pygmaeus and azadirachtin significantly reduced the offspring of N. tenuis females. The sublethal effects of azadirachtin and spinosad on predator reproduction should therefore not be ignored. This information could be useful when selecting the most appropriate insecticide to control T. absoluta in greenhouses and field crops in which M. pygmaeus and N. tenuis are used as biological control agents.     

Comparative efficacy of NeemAzal and local botanicals derived from <Emphasis Type="Italic">Azadirachta indica</Emphasis> and <Emphasis Type="Italic">Plectranthus glandulosus</Emphasis> against <Emphasis Type="Italic">Sitophilus zeamais</Emphasis> on maize

The efficacy of NeemAzal powder, two local neem (Azadirachta indica ) products [neem seed powder (NSP) and neem seed oil (NSO)], as well as a local Lamiaceae, Plectranthus glandulosus leaf powder, applied at four different rates for the control of Sitophilus zeamais was determined. Mortality was recorded 1, 3, 7 and 14 days after S. zeamais infestation, followed by the determination of F₁ progeny production. Grain damage, population increase and grain germination were assessed for treated grains that were stored for 4 months. Grains treated with P. glandulosus powder and NSP had relatively low mortality (5.0–22.5%) after 3 days whereas NeemAzal and NSO had higher mortality (55.0–98.8%). Maximum mortality of 99, 100, 96 and 74% were achieved for NeemAzal (12 g/kg after 14 days), NSO (4 ml/kg after 7 days), NSP (40 g/kg after 14 days) and P. glandulosus powder (40 g/kg, after 14 days), respectively. In the same order, 7-day LC₅₀ values were 0.02 g/kg, 1.46 ml/kg, 12.44 g/kg and 28.9 g/kg. The three neem products greatly reduced progeny emergence, while P. glandulosus powder was less effective. NeemAzal protected the grains against S. zeamais damage better than the local neem products, which in turn provided far better grain protection against the weevil damage than P. glandulosus powder. NeemAzal was superior to the local neem products in grain protection against germination loss, with P. glandulosus being the least effective. NeemAzal and NSO had sufficient efficacy to be a component of an integrated management package for S. zeamais.     

Potential contribution of <Emphasis Type="Italic">Quercus durata</Emphasis> and <Emphasis Type="Italic">Adenostoma fasciculatum</Emphasis> supplemented with <Emphasis Type="Italic">Medicago sativa</Emphasis> on intake and digestibility in sheep and goats

A digestion trial was conducted to estimate the potential contribution of the chaparral browse Quercus durata (leather oak) and Adenostoma fasciculatum (chamise) on intake and nutrient digestion in goats and sheep. Four wether Kiko goats (avg. wt. 22.9 kg) and four wether Targhee sheep (avg. wt. 39.6 kg) were housed in metabolism cages. Alfalfa pellets were used as a dietary supplement. Digestibility of the shrubs was measured by difference and metabolizable energy (ME) and ME intake (MEI) were calculated from digestibility and plants intake values. Oak and chamise had low crude protein (CP) content (6.5 and 4.3% DM) and high content of extractable condensed tannins (17.8 and 9.8% DM). In vitro organic matter digestibility (OMD) and ME for oak and chamise were 35.6 and 33.1% and 5.0 and 4.7 MJ/kg DM, respectively. In vivo OMD (calculated by difference with alfalfa) and MEI, for browse were greater (P < 0.01) for goats fed chamise compared to sheep. In oak, OMD was similar for both animal species but MEI was greater (P < 0.01) for goats. Greater (P < 0.05) DM and CP intakes (per kg BW^0.75) were observed for goats fed either oak or chamise compared with sheep. When an energy source was given as supplement, the potential contribution of chamise and oak to total ME requirements for maintenance was about 58.3 and 60.4% in goats and about 17.1 and 32.9% in sheep, respectively. In consequence, metabolizable energy supplied by these shrubs may not be adequate for maintenance when, during grazing, they are consumed in high proportions with other chaparral plants that may have lower nutritional value than the alfalfa supplemented in this study. Under an appropriate supplementation program, goats could be more effective than sheep to control fuel load in California chaparral, as they consume more chamise and leather oak and obtain more nutrients from them.     

Feeding performance of <Emphasis Type="Italic">Clostera fulgurita</Emphasis> on three clones of <Emphasis Type="Italic">Populus deltoides</Emphasis>

Poplar leaf defoliator, Clostera fulgurita (Walker) larvae were reared on three Populus deltoides clones (PL1, PL5 and PL7) in the laboratory. The nutritional indices were computed for working out the relationship between food consumption and growth rate of 3rd, 4th and 5th instar larvae on three clones. The result showed that the consumption index (CI), approximate digestibility (AD), growth rate (GR), relative growth rate (RGR) and efficiency of conversion of ingested food (ECI) decreased with the increase in the age of the larvae. Efficiency of conversion of digested food (ECD) increased with increase in age of the larvae. GR and RGR varied significantly, indicating that larval development was enhanced on PL1 as compared to PL5 & PL7. The values of AD, ECI and ECD were not affected by the different clones. Feeding and growth indices could be useful to define a defoliation prediction model.     

Genetic diversity and mating system of <Emphasis Type="Italic">bracatinga</Emphasis> (<Emphasis Type="Italic">Mimosa scabrella</Emphasis>) in a re-emergent agroforestry system in southern Brazil

Bracatinga (Mimosa scabrella) is a legume tree species common in the early stages of succession in Araucaria angustifolia forests in southern Brazil. Bracatinga can form high-density monospecific stands called bracatingais. Its traditional management for charcoal production involves maintenance of the seed bank. Our objective was to analyze the genetic diversity and structure of bracatingais to understand the mechanisms by which intraspecific diversity of M. scabrella is created and maintained in landscapes managed by family farmers in their agroforestry mosaics. We analyzed 14 bracatingais using 8 allozyme loci. We compared parental and progeny generation indices (7 loci) and described the mating system (9 loci) of two progenies. Overall diversity was high: A = 2.69, H _o = 0.257, H _e = 0.382 and similar between populations. Overall fixation (F = 0.364) was similar to the fixation index (f = 0.329). The genetic divergence among populations was low (Θ_p = 0.052) but significant. The progenies’ genetic diversity values were similar to those of the previous generation (H _{e pop11} = 0.342 vs. 0.420/H _{e pop10} = 0.432 vs. 0.400). Progenies were compatible with half-sib and full-sib crossing expectations (θ _xy  = 0.204 and 0.194). Our data showed that there is a tendency for genetic structuring caused not only by the reproductive system but also by genetic drift. It is very likely that the high genetic diversity is amplified by internal migration within each bracatingal. This study showed that current landscape management can contribute to maintaining high levels of bracatinga genetic diversity, which contributes to its regional conservation.     

Modelling <Emphasis Type="Italic">Phytophthora</Emphasis> disease risk in <Emphasis Type="Italic">Austrocedrus chilensis</Emphasis> forests of Patagonia

Austrocedrus chilensis forests suffer from a disease caused by Phytophthora austrocedrae, which is found often in wet soils. We applied three widely used modelling techniques, with different data requirements, to model disease potential distribution under current environmental conditions: Mahalanobis distance, Maxent and Logistic regression. Each model was built using field data of health condition and landscape layers of environmental conditions (distance to streams, slope, aspect, elevation, mean annual precipitation and soil pH NaF). We compared model predictions by area under the receiver operating characteristic curve and Kappa statistics. A reasonable ability to predict observed disease distribution was found for each of the three modelling techniques. However, Maxent and Logistic regression presented the best predictive performance, with significant differences with respect to the Mahalanobis distance model. Our results suggested that if good absence data are available, Logistic regression should be used in order to better discriminate sites with high risk of disease. On the other hand, if absence data are not available or doubtful, Maxent could be a very good option. The three models predicted that around 50% (49–56%) of the currently asymptomatic forests are located on sites at risk of disease according to abiotic factors. Most of these asymptomatic forests surround the current diseased patches, at distances lower than 100 m from diseased patches. Management considerations and the scope of future studies were discussed in this article.     

Effects of gamma radiation on the Mediterranean flour moth, <Emphasis Type="Italic">Ephestia kuehniella</Emphasis>, eggs and acceptability of irradiated eggs by <Emphasis Type="Italic">Trichogramma cacoeciae</Emphasis> females

The sensitivity of the Mediterranean flour moth, Ephestia kuehniella, eggs in different stages of development to gamma irradiation was studied and the acceptability of irradiated eggs by Trichogramma cacoeciae females was examined. Eggs ranging in age from 1–24 to 49–72 h were exposed, at 24 h intervals, to gamma radiation dosages ranging from 25 to 400 Gy and effects of gamma radiation on egg hatch and adult emergence was investigated. In addition, the developmental rate of immature stages (larvae and pupae), resulting from irradiated eggs, to the adult stage was examined and the acceptance of irradiated eggs to T. cacoeciae females was evaluated. Results showed that the radio-sensitivity of E. kuehniella eggs decreased with increasing age. Egg hatch in 1–24-h-old eggs was significantly affected at 25 Gy dose and at 75 Gy dose, no egg hatch was observed. When irradiating 25–48-h-old eggs, however, egg hatch was less than 5% at 100 Gy dose, and eggs 49–72-h-old were more resistant; 50 Gy had no significant effect on egg hatch and 300 Gy did not completely prevent it. Irradiation also negatively affected survival to the adult stage. When 25–48-h-old eggs were irradiated, survival to the adult stage was completely prevented at 75 Gy dose and no survival was observed beyond 100 Gy dose in 49–72-h-old eggs. In addition, the rate of development of immature stages resulting from irradiated eggs was negatively affected. While more than 97% of control moths emerged within 30 days, this ratio decreased to 53 and 69% in 1–24 and 25–48-h-old eggs exposed to 25 Gy dose. Furthermore, irradiation positively affected the degree of acceptance of eggs to parasitization; irradiated eggs (≤49-h-old) were more acceptable to T. cacoeciae than cold-treated ones.