摘要:

Under field conditions, the bayberry whitefly,Parabemisia myricae(Kuwana), strongly prefers to oviposition young (actively growing) foliar terminals over middle terminals (meristemetic growth ceased, leaves still soft and light green) and mature terminals (leaves hardened and dark green). Within young terminals, newly laid eggs were concentrated on the apical 5 to 6 cm where leaves were youngest. First instar whiteflies (crawlers) were experimentally placed on young, middle, and mature leaves, and 49, 35, and 0%, respectively, successfully developed to the adult stage.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.254

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

A nonoccluded virus (identified as anAscovirus), isolated from fall armyworm (FAW),Spodoptera frugiperda(J. E. Smith), was tested to determine its compatability with the parasitoidCotesia marginiventris(Cresson). AdultC. marginiventrisreadily transmitted the virus from infected to noninfected FAW larvae. However, the progeny of the parasitoids failed to complete development in host larvae inoculated with the virus before or during parasitization. Fewer parasitoids completed development in host larvae inoculated 4 days after parasitization than in larvae inoculated 5 days after parasitization and in parasitized controls. Mortality was not due to the virus killing the host before the parasitoids could complete development, since the virus-infected larvae lived longer than the parasitized controls. Fewer and smaller parasitoid larvae were found in virus-infected hosts than in parasitized controls when host larvae were dissected 6 days after parasitization.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.258

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

The spatial and temporal distribution of onion maggot (OM)-induced plant damage were studied both within and among onion fields. Distribution of damage within a field of onions was found to be random in untreated plots and aggregated in treated plots early in the season when damage was low. The distribution of plant damage departed significantly from random in all plots later in the season as damage increased. Aggregation or clumping was found to predominate in the regional analysis of plant damage among fields. There were primarily two periods of OM damage during the season, and the first generation of OM larvae caused 65% of the total damage. Possible reasons for the aggregated distribution of damage both within and among onion fields are discussed.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.262

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Adult phenology, relative abundance, and reproductive status of feral moths of the stalk borer,Papaipema nebris(Guenée), were investigated in Iowa, from 1980 to 1983, using collections from blacklight traps. Males constituted 89.2% of trap collections. In all 4 years the first moth was collected between 10 and 21 August and 50% flight occurred between 8 and 14 September. Multiple matings by female moths were common, with the mean number of spermatophores being 2.0, but total numbers ranging from 0 to 7 spermatophores per female. The mean number of spermatophores per female increased throughout the season to 3.0, suggesting that individual female moths are long lived. Although the dates of flights in this study agreed with Illinois dates, the thermal-unit model proposed in previous literature failed to predict satisfactorily adult phenology in Iowa, suggesting that factors other than centigrade degree-day accumulations influence adult stalk borer emergence and subsequent flights.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.267

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Pyrrhalta luteola(Müller) was reared at five constant temperatures from 15.6 to 36.1°C. The optimum temperatures for egg and larval survival were 22.2 and 28.8°C, respectively. Eggs did not hatch at 36.1°; larvae also exhibited high mortality at this temperature. Pupae survived at all temperatures tested with minimal mortality. The developmental rate of allP. luteolastages increased with rise in temperature. Embryonic, larval, and pupal developmental threshold temperatures were estimated at 11.3, 11.0, and 11.1°C, respectively. Mean degree-day (°C) accumulations required for completion of life stages were: 78.9 for egg, 268.1 for larva, and 89.3 for pupa. Accumulated degree-days>11.1°C during outdoor development ofP. luteoladid not differ significantly from those calculated from laboratory data.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.272

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Mean development rate of eggs of the Colorado potato beetle,Leptinotarsa decemlineata(Say), at 10 constant temperatures over the range 15 to 33°C is fit with a bounded sigmoid curve. The distribution of development rates is modeled using a temperature-dependent normalizing function and a sigmoid curve fit to cumulative development. When eggs are alternated between 25 and 35°C for limited durations, development rates vary from those predicted using constant-temperature results. This is explained as a product of selective mortality and time lags in shifts between rate-controlling mechanisms. Mean development rate of larvae at 10 constant temperatures over the range 15 to 33°C is fit with a simple sigmoid curve, and distributed development of larvae is described in a manner similar to that used to describe the distribution of egg development rates. Total feeding of the 4 larval instars over the range 15 to 33°C is described as a constant (instars 1 and 2) or a 2nd-order polynomial (instars 3 and 4). Mean development rate of pupae at 11 constant temperatures over the range 10 to 31°C is fit with a simple sigmoid curve.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.275

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

The developmental rate of eggs ofTrichosirocalus horridus(Panzer) in the laboratory was 0.0343 – (0.0071 × temp in °C). Egg hatch threshold was 4.8°C. Successful overwintering of eggs was affected by low temperatures at initial exposure. Eggs survived well when initially exposed to relatively high field temperatures between early November and mid-December, and from late February to March. However, eggs initially subjected to low temperatures between 15 December and 9 February suffered high mortality, although those surviving were not greatly affected by subsequent extended exposure to low temperatures. Most of the eggs initially exposed to field temperatures during this cold period hatched at about the same time. Eggs first exposed in November began hatching outside by mid-March.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.284

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Seedcorn maggot flies,Delia platura(Meigen) showed an innate oviposition preference for lima beans over acorn squash seeds and for snap beans over watermelon or cantaloupe seeds in laboratory tests. These preferences were not significantly altered by prior exposure of adult flies over a 3-week period to a single type of seed. Flies reared as larvae on single types of seeds also did not differ significantly in their oviposition preferences. Total numbers of eggs laid varied, depending on both prior exposure and larval host.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.289

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

To determine an optimal sex pheromone blend for attractingHeliothis virescens(F.), field studies were conducted using pheromone-baited cone traps. Tests with various combinations of the seven components found in sex pheromone glands indicated that a blend of (Z)-11-hexadecenal, (Z)-9-tetradecenal, hexadecanal, and (Z)-11-hexadecenal dispensed to rubber septa at a ratio of 65.1:1.6:32.6:0.7 was optimal. Blends containing no (Z)-11-hexadecenol, or those with levels greater than 1% relative to (Z)-11-hexadecenal, were generally found to be suboptimal.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.293

出版商:Oxford University Press    

年代:1985

数据来源: OUP

摘要:

Effects of tungro virus-infected rice plants on the behavior and biology of the vectorNephotettix virescens(Distant) were investigated. In a choice test, tungro-infected plants attracted significantly moreN. virescensindividuals than did healthy plants, but after 24 h more individuals settled on healthy plants. Insect feeding on diseased plants was disrupted and the quantity of food ingested and assimilated was significantly less than on healthy plants. Although there was no significant difference in the number of nymphs that became adults on infected and healthy plants, the growth period was prolonged on diseased plants. A significant reduction in adult longevity, fecundity, egg hatchability, and population growth was observed on tungro-infected plants. However, oviposition was not affected. Tungro-infected plants had a significantly higher free sugar content but soluble protein was significantly lower than in healthy plants.

ISSN:0046-225X    

DOI:10.1093/ee/14.3.297

出版商:Oxford University Press    

年代:1985

数据来源: OUP