摘要:

Lindane applied to pines as an aqueous 0.5% spray for control of the southern pine beetle,Dendroctonus frontalisZimmermann, caused long-term reductions in litter and soil mesofaunal populations in the mountains of North Carolina. Mites, collembolans, and other arthropod fauna did not return to pretreatment numbers for at least 2 yr, and soil mesofauna remained below initial populations even after 963 d. Although lindane remained in the litter and soil for about 3 yr, it did not move downslope in quantities that threatened water quality. In the Piedmont, aqueous 0.5% lindane and 2.0% fenitrothion were applied directly to the forest floor. Although initial fenitrothion residues were 7.5 times greater than those of lindane, the transient nature of these residues and reduced effects on mites and collembolans indicate it has a shorter-term effect on soil and litter fauna.

ISSN:1754-5692    

DOI:10.1093/ee/18.2.245

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

When given 30 eggs ofNilaparvata lugens(Stal) daily, males and females ofCyrtorhinus lividipennisReuter took 10.8 and 13.0 d, respectively, to develop from first instar. The males consumed 49.0 eggs and the females, 59.2 eggs. The mean body length of adult males was 2.6 mm and females, 3.1 mm; mean longevity was 9.6 d for the males and 14.4 d for the females. Lifetime egg consumption was 43.8 eggs by the males and 123.6 eggs by the females. Mean lifetime fecundity by unmated females was 34.0 eggs. When 20 or fewer eggs or 10 or fewer first-instarN. lugenswere given daily as food, nymphal survival, adult longevity, and fecundity decreased. Individuals offered 20 or moreN. lugenseggs consumed significantly more than those offered fewer eggs, but this did not result in a decrease in development time or in adult size.C. lividipennisadults that were fed daily withN. lugensnymphs (5 or 10 first, second, or third instars) also had a shorter life span and laid no eggs. Adults offered 10 second or third instars lived significantly longer than those on other regimes. Our results suggest thatC. lividipennisnymphs need only small amounts of food to survive to adulthood under field conditions, especially at the beginning of the rice growing season, whenN. lugenseggs are relatively scarce.

ISSN:1754-5692    

DOI:10.1093/ee/18.2.251

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

The reduction in net photosynthesis caused by tomato russet mite (TRM),Aculops lycopersici(Massee), feeding was measured. A significant relationship between net photosynthesis and mite-days per cm2of leaflet was observed. Photosynthesis of healthy tomato leaflets did not increase to compensate for photosynthesis reduction in damaged leaflets. Studies suggest that destruction of guard cells and subsequent reduction of leaf gas exchange were responsible for photosynthesis reduction, and that no photosynthesis-reducing phytotoxin is present in TRM saliva.

ISSN:1754-5692    

DOI:10.1093/ee/18.2.256

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Female eastern spruce budworm,Choristoneura fumiferana(Clemens), inoculated sublethally as fourth or fifth instars withNosema fumiferanae(Thomson), exhibited significant reductions in size, fecundity, and total egg complement. Mating success and egg fertility were similar for treated and control insects. The presence of disease improved the positive correlation between fecundity or total egg complement and female pupal weight without significantly reducing the slope. Total egg complement was negatively correlated with disease load. A subsample of progeny reared from each fertile mating indicates 100% transovarial transmission efficiency at the spore dosages provided. Diseased progeny experienced twice the larval mortality, and surviving individuals were approximately 25% smaller and took 17% longer to complete development than healthy progeny. Maternal disease load was a significant, positive factor in percentage progeny mortality and male pupal weight.

ISSN:1754-5692    

DOI:10.1093/ee/18.2.261

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

During the months of July through early September from 1984 through 1986, large numbers of live, predominantly female, western corn rootworm (WCR),Diabrotica virgifera virgiferaLeConte, adults appeared on the southern shoreline of Lake Michigan on 16 occasions. Correlation of the numbers of beetles washed ashore with the passage of synoptic scale weather systems shows that the beetles accumulate on the shoreline after the passage of cold fronts starting at approximately the date of maximum emergence of WCR and continuing for 24–49 d. The WCR deposited on the shoreline appear to have originated from fields local and distant from the shoreline, with local WCR predominant in deposition events near the time of local maximum emergence and long-distance WCR predominant in deposition events later in the season. Insects appear to be carried along the front. Precipitation does not appear to result in greater deposition of WCR onto the surface, therefore descent of the insect must be by active flight or downdrafts in the front.

ISSN:1754-5692    

DOI:10.1093/ee/18.2.266

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Populations ofCochylis hospesWalsingham were monitored with pheromonebaited traps from 1985 to 1987 at 47 locations in North Dakota, South Dakota, Montana, Minnesota, Iowa, Ohio, Indiana, New Jersey, Maine, Kansas, Arkansas, Texas, Georgia, and Oregon. Traps were placed at the edge of sunflower fields and were checked from 20 June to the end of the flight period (August or September, depending on the locality). In North Dakota and Minnesota, emergence of adults from the soil and oviposition also were observed through the season. Results indicated that in eastern North Dakota and Minnesota, emergence of adults and oviposition were concurrent in time with flight activity as indicated by pheromone trap catches. In western North Dakota, western South Dakota, Kansas, Indiana, and southwestern Ohio, moths emerged later than in the eastern Dakotas, Minnesota, and central Iowa.C. hospeswas recorded for the first time in Ohio, Arkansas, Texas, Kansas, and Oregon.

ISSN:1754-5692    

DOI:10.1093/ee/18.2.273

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

The distribution of adult aquatic insects in the mixed evergreen forest adjacent to Big Sulphur Creek, Sonoma Co., Calif., was examined using sticky traps (0.26 m2each) that were placed in trees at three distances (5, 40, 150 m) from the stream and at three heights (2, 5, 8 m) above the ground. Species richness, number of individuals, and biomass of aquatic insects, and number of individuals for seven of 12 common aquatic insect taxa decreased (P ≤ 5 0.05) as distance from the stream increased. Species richness, number of individuals, and biomass of aquatic insects showed no relationship with height above the ground, but of the 12 common taxa, three were most abundant near tree tops and one was most abundant near tree bases (P ≤ 0.05). Adult aquatic insects represented 36.9 and 15.4% of total arthropod numbers and 25.3 and 10.7% of total arthropod biomass at the 5-m and 150-m sites, respectively. The abundance of adult aquatic insects in the forest bordering this stream suggests that adult aquatic insects provide an important conduit for energy and nutrients from the aquatic system to the terrestrial food web.

ISSN:1754-5692    

DOI:10.1093/ee/18.2.278

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

The relative importance of three sources of larval mortality (host plant resistance, intraspecific competition, and natural enemies) was evaluated for a population of leafgalling sawflies,Pontaniasp., nearP. pacificaMarlatt, on arroyo willow,Salix lasiolepisBentham, at a site in Flagstaff, Ariz., from 1981 to 1984. The ratio of the percentage of sawfly larvae killed by natural enemies to the percentage lost to host plant defenses (i. e., abortion, defined as an aborted formation of a gall resulting from death of the egg or small larva) was 1.53:1. Mortality from abortion was divided into a host plant resistance component (constitutive abortion, e.g., a plant resistance factor preventing establishment of the egg or small larva) and an intraspecific competition-mediated component (because abortion increased as within-leaf gall densities rose). Natural enemies caused twice as much mortality as plant resistance and 6.36 times greater mortality than intraspecific competition. These results support the hypothesis that third-trophic-level effects exert a stronger selective pressure on many insect populations than competition for limiting resources. There was evidence that intraspecific competition for limiting food resources occurred for thesePontaniasp. sawflies; increased within-leaf gall densities had a density-dependent, linear, negative effect on gall size, and consequently, on larval biomass because sawfly size was positively correlated with gall size. However, only about 3% of the variation in gall size was explained by within-leaf gall density. Thus, gall (and larval) size were only weakly affected by intraspecific competition.

ISSN:1754-5692    

DOI:10.1093/ee/18.2.284

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Currently, a mass rearing technique for the egg parasitoid,Edovum puttleriGrissell, of the Colorado potato beetle (CPB),Leptinotarsa decemlineata(Say), is lacking. An important component of such a system would be maximization of CPB egg production per day. The present studies characterized the effects of two factors, food plant and diapause history, on CPB egg production. Two greenhouse experiments determined the survivorship and fecundity of CPB on three food plants, potato,Solanum tuberosum tuberosumL. cv. Pungo; tomato,Lycopersicon lycopersicum(L.) Karsten var.lycopersicum, cv. Pick Red; and eggplant,S. melongenaL. cv. Harris Special and cv. White. A third study compared the survivorship and fecundity of a field-collected population that had been in a state of diapause at 10°C for 6 mo with that of CPB from the same population cultured on potato in the greenhouse for the same period. Survivorship and longevity of adults did not differ among most food plants. Total egg mass and egg production per female and egg mass size were greatest on potato followed in decreasing order by tomato and ‘Harris Special’ eggplant in one study, and were greatest on tomato followed by potato, ‘White’ eggplant, and ‘Harris Special’ eggplant in the second study. Fecundity per day was greatest on potato and tomato in the first and second studies, respectively. Adult longevity, survivorship, total egg mass and egg production per female, and egg mass size did not differ between CPB that had diapaused and those that had not diapaused; however, fecundity per day was greater for CPB that had diapaused than for CPB that had not diapaused. The importance of these data in the development of a mass rearing technique forE. puttleriis discussed.

ISSN:1754-5692    

DOI:10.1093/ee/18.2.291

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Newly emerged gypsy moth,Lymantria disparL., larvae were released onto tree stems that were disinfected with sodium hypochlorite, sprayed with nuclear polyhedrosis virus (NPV), or left untreated to assess the importance of contaminated bark surfaces in transmitting NPV to newly emerged neonates after an epizootic. NPV mortality among released larvae was related to the degree of contamination of the bark surface and indicates that bark surfaces may play an important role in transmitting NPV, particularly in the year following an epizootic.

ISSN:1754-5692    

DOI:10.1093/ee/18.2.298

出版商:Oxford University Press    

年代:1989

数据来源: OUP