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21.
An experiment was conducted to assess the use of a multisurface trap for the capture ofEphestia kuehniella Zeller (Lepidoptera: Pyralidae) in a horizontal-type warehouse in southern Greece, filled with approx. 200 tons of wheat. This type of trap consists of five white rectangular adhesive cardboard strips, suspended vertically from a cruciform apparatus. Four different types of traps were placed in the warehouse, one at each corner (pheromonebaited multisurface, unbaited multisurface, pheromone-baited single, and unbaited single trap). Traps were checked at 15-day intervals from July to November 2000. Approx. 85% of the total number of captured adults were recorded by late August. The highest numbers of moths were observed from mid-July until mid-August. As compared with the unbaited multisurface trap, the baited single and the unbaited single, the baited multisurface traps caught approximately 4.2, 4.8 and 41.2 times moreE. kuehniella adults, respectively. For all trap types, significantly higher numbers of adults were captured at the lower part of the sticky surface, as compared with the central and upper parts (P<0.05). A considerable percentage of the moths captured was found at the edges of the trapping surfaces, especially on the unbaited traps, where the figure exceeded 36%. With the exception of the unbaited single trap, significantly more adults were recorded at the lower edge of the trap (P<0.001), while the upper edge — as compared with the other edges — captured the fewest adults. Exposure of the trapping surface to illuminated areas of the warehouse, or location of the trapping surfaces close to walls, had no significant effect on captures. http://www.phytoparasitica.org posting Dec. 16, 2002.  相似文献   
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23.
  1. The Kemp’s ridley (Lepidochelys kempii) is the world’s most endangered sea turtle species. Predominately nesting at only one beach in Mexico, this species declined to an estimated 300 females in the mid-1980s. Conservation efforts in the United States and Mexico, including a head start programme in southern Texas in which hatchlings were reared in captivity for several months before being released into the wild, resulted in the recovery of this species.
  2. Although genetic data have previously been used to assess the success of the head start programme and dispersal of individual adults, data on immature turtles sampled at foraging areas and adult females sampled at the main nesting beach in Mexico are lacking. Genetic characterization of immature individuals is important for understanding recruitment, survival, and population demography, while genetic data on individuals from Mexico are essential for understanding dispersal and overall genetic diversity in this species.
  3. To address these gaps, mitochondrial DNA data were collected from 106 immature individuals sampled at four different foraging sites in the northern Gulf of Mexico and from 18 nesting females at the primary nesting beach in Mexico.
  4. Two previously unknown mitochondrial DNA haplotypes were discovered among the immature individuals.
  5. Except for these two new haplotypes, the genetic diversity of immature individuals in the northern Gulf of Mexico closely corresponds to that of adults sampled in Mexico, which suggests that much of the diversity within the nesting population can be found among immature animals dispersing to foraging grounds, including locations in the northern Gulf of Mexico.
  6. Continued monitoring of the genetic variation of different life stages of this species across its distribution range will help assess the success of conservation programmes by ensuring the maintenance of genetic diversity and representation of this diversity across the species’ distribution range.
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24.
Field studies were conducted to assess the population and the spatial dynamics of the predatory bugMacrolophus costalis Fieber (Hemiptera: Miridae) and of its prey, the aphidMyzus persicae (Sulzer) (Hemiptera: Aphidoidea), on tobacco. From an untreated tobacco field in Tithorea (central Greece), tobacco leaves were collected from the upper and the lower half of the plants from June until September, in 1999 and 2000. The numbers ofM. costalis andM. persicae individuals per leaf were counted. Most aphids were observed during July and August (early and mid season), with densities dropping markedly in September. In contrast,M. costalis population densities increased late in the season (September). Significantly higher numbers of aphids were found on the upper half of the plants than on the lower half. In contrast, significantly moreM. costalis individuals were observed on the lower half. Iwao’s Regression Analysis was used in order to characterize the spatial pattern of the two species. According to this model, in both sampling seasons, aphids andM. costalis nymphs displayed an aggregated spatial pattern, whileM. costalis adults were found to be randomly distributed among sampling units. Although moreM. costalis individuals were recorded on leaves with relatively high aphid densities, this species did not react numerically to changes in prey density. In addition, a significant number of bugs were found on leaves with low aphid densities or no aphids at all. http://www.phytoparasitica.org posting Dec. 18, 2002.  相似文献   
25.
Populations of Hippopotamus amphibius have declined throughout Africa in recent years, and are expected to decline further. An understanding of the population genetics of individual populations of hippos is necessary for effective management. To that end, we sequenced a portion of the mitochondrial DNA (mtDNA) control region or D-loop from 37 H. amphibius, from six herds in the central region of Kruger National Park (KNP), Republic of South Africa. We amplified a 453 bp segment by PCR, and identified 21 polymorphic sites and seven haplotypes. All of these haplotypes are private alleles, not found in other populations of hippos from southern Africa. Overall nucleotide diversity (π) was 0.01739, and haplotype diversity (hd) was 0.8273, within the range observed in other parts of Africa. Mismatch analysis conformed more closely to a model of constant population size than either rapid demographic or spatial expansion. An analysis of molecular variance demonstrated no significant differentiation among herds, and Mantel tests showed no significant relationship between geographic and genetic distance among herds separated by up to 47 km (measured as Euclidean [x,y] distance) or 77 km (measured along rivers). Over this range, the population appears to be a single panmictic unit. A test of the hypothesis that calves are more likely to share a mtDNA haplotype with an adult female in the same herd than an adult female from a different herd was not significant.  相似文献   
26.
Several naturally discovered or laboratory-synthesized pyrrole compounds have insecticidal, acaricidal and microbial properties. The novel sulfanyl 5H-dihydro-pyrrole derivatives exhibit certain antioxidant activities. However, there is a knowledge gap whether these substances are potent grain protectants against stored-product insect pest species. In this context, we evaluated the insecticidal activity of five novel pyrrole derivatives (under the trivial names 3a, 3g, 3l, 3m, 3h), against larvae of Tribolium confusum Jaquelin du Val and Ephestia kuehniella Zeller at different doses (0.1, 1 and 10 ppm), exposure intervals (7, 14 and 21 days or 1, 2, 7, 14, 21 days), temperatures (20, 25 and 30 °C), relative humidity (RH) (55 and 75 %) levels and commodities (wheat, maize, barley). The pyrrole derivative 3a exhibited the highest insecticidal activity, while 3g, 3l, 3m and 3h caused similar mortality against larvae of T. confusum. Apart of the level of efficacy, all tested pyrrole derivatives performed similarly according temperature. We found that increase in temperature increased mortality in the majority of the tested combinations. Generally, the pyrrole derivatives caused the highest mortality levels at 30 °C. The pyrrole derivatives 3a, 3g, 3l and 3m were affected by relative humidity at almost all combinations tested. The 75 % level of RH moderated the efficacy of the pyrrole derivatives, while the 55 % enhanced it. Mortality of T. confusum and E. kuehniella on maize was much lower on treated maize than barley or wheat. However, 100 % control of both species was recorded only on treated barley. The results of the present study indicate that the pyrrole derivatives tested could serve as grain protectants against noxious stored-product insects under certain biotic and abiotic conditions.  相似文献   
27.
BACKROUND: Fipronil is an insecticidal pyrazole that is commonly used as an insecticide in field crops, urban pesticide and veterinary medicine, but there are no reports of its evaluation against stored‐product insects. Three series of laboratory bioassays were conducted to assess fipronil as a potential grain protectant against adults of Sitophilus oryzae (L.), Tribolium confusum Jacquelin du Val, Rhyzopertha dominica (F.) and Prostephanus truncatus (Horn). Factors such as dose (0.01, 0.1, 1 and 10 mg fipronil kg?1 grain), exposure interval (24 h, 48 h, 7 days and 14 days), temperature (20, 25 and 30 °C), relative humidity (RH; 55 and 65%) and commodity (wheat, maize, barley and paddy rice) were evaluated with regard to their impact on the insecticidal activity of fipronil. Progeny production was assessed after 64 days of exposure. RESULTS: At doses of < 1 mg fipronil kg?1 grain, efficacy of fipronil was enhanced by an increase in temperature from 20 to 25 °C against S. oryzae or R. dominica for exposures of > 48 h and against T. confusum or P. truncatus for exposures of > 24 h. A further increase in temperature from 25 to 30 °C, although it enhanced efficacy at doses of < 1 mg fipronil kg?1 grain against S. oryzae at all exposure intervals and against T. confusum after 7 days of exposure, it was negatively associated with efficacy against R. dominica or P. truncatus for exposures of > 24 h. By contrast, increase in RH did not have a significant impact on efficacy of fipronil. Although the performance of fipronil among the tested commodities was species dependent, this substance appeared to be less effective in paddy rice than in barley, maize and wheat. Regardless of the treated commodity, progeny production of all the tested species was almost suppressed with doses higher than 0.1 mg fipronil kg?1 grain. CONCLUSIONS: Fipronil appeared to be a very effective alternative to the existing substances in stored‐grain protection at doses equal to or higher than 1 mg fipronil kg?1 grain, and thus these doses require further evaluation in terms of safety for the consumer and residues on stored products. Copyright © 2010 Society of Chemical Industry  相似文献   
28.
Laboratory tests were conducted to assess the insecticidal and residual effects of three diatomaceous earth (DE) formulations, Insecto, PyriSec and SilicoSec, against Tribolium confusum Jacquelin du Val on wheat and maize. Quantities of wheat and maize were treated with the above formulations at 500, 1000 and 1500 mg kg(-1) and stored at 25 degrees C and 55% relative humidity (RH). Samples were taken on the day of storage and every 30 days until completion of a 360 day period of storage. Adults of T. confusum were exposed to these samples at 25 degrees C and 55% RH and the mortality was measured after 24 and 48 h and 7 and 14 days of exposure. Adult mortality was higher on wheat than on maize. At the beginning of the storage period, mortalities after 14 day exposure on maize treated with the highest rate were 60, 63 and 81% for Insecto, PyriSec and SilicoSec respectively, while on wheat the mortality was 100% for all DEs. On the same commodities 360 days after treatment the respective mortality figures for wheat were 99, 98 and 100%, while in the case of maize they did not exceed 7%. Generally, mortality at exposures < or =48 h decreased with increasing storage time. Furthermore, although mortality on wheat increased with dose, the increase in DE dose from 1000 to 1500 mg kg(-1) resulted in only a small increase in mortality. Thus a DE treatment of 1000 mg kg(-1) was shown to provide long-term protection of wheat against T. confusum, although higher DE application rates and exposure intervals are needed for a satisfactory level of protection of maize against this pest.  相似文献   
29.
Nickolas  Henry  Williams  Dean  Downes  Geoff  Tilyard  Paul  Harrison  Peter A.  Vaillancourt  René E.  Potts  Brad 《New Forests》2020,51(1):137-158
New Forests - Eucalyptus globulus is widely grown for pulpwood production in temperate regions of the world. However, there is increasing interest in using it for solid-wood products. We studied...  相似文献   
30.
The effects of aluminum (Al) on nitrate reductase activity, plastid pigment content, and mineral element composition in wheat, rye, and triticale seedlings were studied. Different responses of the plant species to Al content in the growth solution were observed. Under conditions of different Al concentrations (from 1 to 10 ppm), nitrate reductase (NR) activity increased in wheat and triticale, while in rye an interference with nitrate reductase by Al was observed. A definite tendency in plastid pigment content changes independent on Al levels was not found. The chlorophyll “a”;, chlorophyll “b”;, and carotenoid contents were influenced in a different way in wheat, rye, and triticale seedlings. A positive effect of 1, 5, and 10 ppm Al on the nitrogen (N) content in the shoots of wheat and rye was observed. The N content in the shoots of triticale was not affected by the presence of Al. The presence of Al in the nutrient solution led to a tendency toward reduction of potassium (K), calcium (Ca), and magnesium (Mg) contents in the shoots of rye seedlings, a reduction of K in the shoots and manganese (Mn) content in roots of wheat, and a reduction of K in both shoots and roots and an accumulation of Mn in triticale roots. In general, our investigation on the effect of Al in the early stages of wheat, rye, and triticale development showed that a large number of biochemical and physiological parameters are required to characterize the plant responses to Al stress.  相似文献   
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