摘要:

In the laboratory at a photoperiod of 16:8 (L:D) and 21°C, larvae ofLobesia botrana(Denis&Schiffermueller) developed faster on grapes and apples infected with the fungusBotrytis cinereaPersoon than on healthy grapes and apples. The duration of each of the five larval stadia on healthy berries was 5.3, 4.3, 4.2, 6.3, and 8.5 d in 1981, and 6.2, 4.3, 4.8, 6.9, and 9.7 in 1982. On infected berries the respective durations of the stadia were 5.8, 5.2, 5.1, 5.2, and 6.3 d in 1981, and 6.6, 4.2, 4.6, 5.3, and 8.0 d in 1982. The duration of the fourth and fifth stadia was significantly shorter on infected berries. When the larvae grew on infected berries during either the third or fourth stadia, the duration of the fourth and fifth stadia on healthy berries was significantly shortened. This faster larval growth was observed when the berries were infected 10–12 d before placing the larvae on them, but not when infected 25 d before placing the larvae on them. The yield in adults, when the larvae were reared on grape berries and apples infected with the fungus, was higher than on healthy fruits. This resulted in a 2.2- to 2.5-fold population increase on grapes and 1.4- to 2.7-fold on apples, as compared with fruits not infected with the fungus.

ISSN:1754-5692    

DOI:10.1093/ee/17.1.1

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Three bacterial isolates, aFlavobacteriumsp.,Erwinia herbicola, andXanthomonas campestris, stimulated seedcorn maggot,Delia platura(Meigen), oviposition when tested either alone or in combination. Twenty bacteria with varying abilities to inhibit growth of these stimulatory bacteria were isolated from soil. These antagonistic bacteria either stimulatedD. platuraoviposition themselves or did not reduce inocula of the other organisms enough to reduce egg laying. In observation experiments, flies stayed longer and laid more eggs on inoculated substrates, even when they could not actually contact the bacterial inoculum during oviposition.

ISSN:1754-5692    

DOI:10.1093/ee/17.1.7

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Logistic equations to describe height and diameter growth of budded, fieldgrown pecan,Carya illinoensis((Wang.) K. Koch.), nursery stock were developed for several diameter classes of four cultivars—‘Cheyenne,’ ‘Stuart,’ ‘Elliott,’ and ‘Desirable.’ The equations were used to describe impact of feeding on final tree size by larvae of the pecan bud moth,Gretchena bolliana(Slingerland), during May, June, and July. Simulated bud moth damage (pinched terminal buds) occurring in Mayor June significantly reduced both final scion height and diameter of pecan nursery stock. Pecan nursery stock damaged in July was not significantly different (P= 0.05) from the undamaged control in final scion height and diameter. Recommendations to growers based on this study can significantly reduce pesticide use to control pecan bud moth.

ISSN:1754-5692    

DOI:10.1093/ee/17.1.13

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Traditional age-specific life table analysis does not take variable development rates into account and deals only with the female population. In this paper, rearing and harvesting of specific life stages are analyzed in the context of a general age-stage, two-sex life table. The question of selecting optimal harvest and discard strategies for the design of insect mass rearing facilities is discussed. The method is demonstrated using data collected from a culture of the potato tuberworm,Phtharimaea aperculella(Zeller).

ISSN:1754-5692    

DOI:10.1093/ee/17.1.18

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Raw data analysis of an age-stage, two-sex life table, incorporating variable development rates among individuals, is described, using data obtained from rearing the potato tuberworm,Phthorimaea operculella(Zeller) (Lepidoptera: Gelechiidae). The intrinsic rate of increase is calculated with respect to both sexes. The stable age-stage distribution, stable age distribution, and the stable stage distribution are also calculated. Different results are obtained when the same data are analyzed using the traditional age-specific life table (Leslie matrix or Birch's method). These differences occur because the traditional age-specific life table deals only with female populations and does not take variable development rates among individuals into account. The relationship between the net reproduction rate and mean female fecundity in the age-stage, two-sex life table is described by a simple formula.

ISSN:1754-5692    

DOI:10.1093/ee/17.1.26

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Adult phenology, abundance, and reproductive status of the locust twig borer,Ecdytolopha insiticianaZeller, were investigated during 1983 and 1984 in southeastern Kentucky using blacklight traps. First adults were captured in the second week of May and a second generation began to emerge in early July. No adults were captured after late August. Multiple matings by females were common, and egg-bearing females were present throughout most of the season. Adult females emerge with a large proportion of oocytes yolked; they oviposit primarily during the first few days following eclosion when fed a 10% honey/water solution. Males constituted 77.4% of the blacklight collection, but laboratory emergence data indicated a 1:1 sex ratio.

ISSN:1754-5692    

DOI:10.1093/ee/17.1.35

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Developmental rates and survival of nondiapausing redbanded leafroller (RBLR),Argyrotaenia velutinana(Walker), eggs, larvae, and pupae were determined at eight constant temperatures: 5, 10, 15, 20, 25, 30, 32, and 35°C under a regime of 16:8 (L:D) photoperiod. Mean duration for each of five larval stadia by sex was determined at 25°C and protandry was shown. There was no survival at 5 and 35°C. Survival of eggs and larvae increased to 96.5 and 98.8%, respectively, at temperatures up to 20°C and fell at higher temperatures while pupal survival was highest at 25°C (92.1%). Temperature versus developmental-rate data were incorporated into linear and nonlinear models of temperature-dependent development to simulate adult emergence at variable temperatures. Lower developmental thresholds, degree day (DD) requirements, and percent of total developmental time for all stages individually and combined for six- (10, 15, 20, 25, 30, and 32°C) and four- (10, 15, 20, and 25°C) temperature linear models are given. Completion of one generation with the six-temperature linear model required 909 DD over a lower developmental threshold of 5.5°C, while the linear portion of the temperature-developmental rate relationship (four-temperature model) required 676 DD over 8.0°C. Parameters for a nonlinear model were established at all temperatures for each stage and for the combination of all stages. Simulations based on the nonlinear and the four-temperature linear model were validated by comparison with observed within-season male flight peaks using pheromone trap catch data from eight apple orchards. Linear models ran 0–4 d faster than nonlinear models. Of 18 actual flight peaks simulated, linear models simulated 11 and nonlinear models simulated nine within ±7 d of observed orchard flight peaks. Only one simulation predicted adult emergence early, all other inaccurate simulations predicted adult emergence 8–17 d late. Analysis of seasonal flight catch in each orchard and results of the model simulations suggest the presence of four generations of RBLR annually in North Carolina.

ISSN:1754-5692    

DOI:10.1093/ee/17.1.40

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

In a laboratory flight tunnel bioassay, optimum attraction of female papaya fruit flies,Toxotrypana curvicaudaGerstaecker, to the sex pheromone 2,6-methylvinylpyrazine was obtained at release rates of 550–1,650 ng/h. Females became responsive to sex pheromone on the fifth day after eclosion, with response peaking on seventh and eighth days postemergence, coincident with ovarian maturation. Responses to pheromone did not decrease qualitatively or quantitatively after mating. A diel pattern to pheromone response was observed with a midday (5- to 7-h into a 12-h photophase) response period for mature, unmated papaya fruit fly females and a broad afternoon response period for mated females.

ISSN:1754-5692    

DOI:10.1093/ee/17.1.47

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Five species of citrus, including 52 cultivars, were sampled, and field infestations byAnastrephaspp. andCeratitis capitata(Wiedemann) were ranked. Fruit factors including sugar content, pH, thickness and mechanical resistance of the peel, and oil-gland density and volume were measured and compared with infestation levels.A. ludensmade up 98%, otherAnastrephaspp. 1%, andC. capitata, which infested only seven cultivars, 1% of the total infestation. Grapefruits were infested primarily byAnastrephaspp., and tangerines primarily byC. capitata. Significantly more fruit flies emerged from mature than green or half-green fruits. Mechanical resistance, thickness, and estimated oil volume of the peel together were negatively correlated with infestation. For mature fruits, no correlation with infestation, was found between the thickness of the rind or the mechanical resistance of the peel. However, when the data from green and half-ripe fruit also were pooled, there was an inverse correlation between these parameters and infestation levels. The oil volume of the flavedo was inversely correlated with the infestation.

ISSN:1754-5692    

DOI:10.1093/ee/17.1.52

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Greenbug,Schizaphis graminum(Rondani), clones were collected in fields from eight localities in the central United States. Two clones collected from sorghum,Sorghum bicolor(L.) Moench, and one clone obtained from the Agronomy Greenhouse, North Dakota State University, Fargo, N. Dak. (initially isolated on barley in 1968) were identified as biotype C. Six other clones collected from sorghum fields were identified as biotype E. All clones were cultured in the laboratory on barley,Hordeum vulgareL.; oats,Avena sativaL.; ‘Piper’ sudangrass,Sorghum sudanensisBailey; and Kentucky bluegrass,Poa pratensisL., as standard diets. All clones were tested for fecundity during 10-d experiments in two chambers with automatically controlled 14:10 (L:D) photoperiod at 24 ± 1°C and 25% relative humidity. Fecundity of biotypes C and E was determined on the same host plants and on corn,Zea maysL., susceptible sorghum, biotype-C-resistant ‘IS-809’ sorghum, and biotype-C-resistant ‘Amigo’ wheat. Clones of the same biotype from different localities did not show differences in fecundity on the same host plants after being previously cultured on the same host plants. Biotype C showed greater fecundity on Kentucky bluegrass and on ‘Piper’ sudangrass after culturing on barley. Biotype E had greater fecundity on oat and ‘Piper’ sudangrass after culturing on barley. On corn, greenbugs did not survive longer than a week. All greenbugs grew slowly on ‘Amigo’ wheat and ‘IS-809’ sorghum. Greenbugs had higher fecundity on ‘IS-809’ sorghum than on ‘Amigo’ wheat.

ISSN:1754-5692    

DOI:10.1093/ee/17.1.59

出版商:Oxford University Press    

年代:1988

数据来源: OUP