摘要:

Adult male bollworm,Heliothis zea(Boddie), moths were collected from sex pheromone traps located in Arkansas and were examined for pollen. Pollen was found on 68.3% of the moths, primarily on the proboscis or eye area. Pollen of false mesquite,Calliandra, and ape's earring,Pithecellobium, were found on moths during each of 2 yr. Neither plant occurs in Arkansas;Calliandra'sclosest distribution to Arkansas is south central Texas, andPithecellobiumoccurs in south Texas near the Mexican border. The presence of these pollens onH. zeaindicates immigration from at least 750 km to the Arkansas capture sites.

ISSN:0046-225X    

DOI:10.1093/ee/16.5.1148

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Field studies in Florida using sticky traps baited with A-II synthetic female pheromone [(2S,3S,7S)-3,7-dimethylpentadecan-2-yl acetate] or a series of live virginNeodiprion lecontei(Fitch) females were conducted to determineN. leconteimale flight responses at different heights above ground. A-II and virgin females were interchangeable in eliciting male responses. Most males (≥84%) responded either to A-II-or female-baited traps placed at firetowers at 1 m, rather than at 14 or 28 m. The proportion of males responding to A-II at 1 m usually decreased in competition with the attraction of A-II or females at 14 m. When A-II-baited traps were placed at 1, 2, 3, 4, and 5 m per host pine 6 m tall, there was no significant (P>0.05) difference in the mean numbers of males caught per trap placed on trees with branches and foliage (possible host factor) artificially removed, than on intact (control) trees. When A-II-baited traps were placed singly at either 1, 2, 3, 4, or 5 m high per tree in trees with branches and foliage present, there was no significant (P>0.05) difference in mean catches. These data indicate that single A-II-baited traps will effectively attract males when placed in young pine stands on stakes at 1 m or on trees at ca. 2 m. Attempts to eradicateN. leconteiby continuous trapping of males at such heights probably would fail when virgin females were present in the crowns of large host trees nearby.

ISSN:0046-225X    

DOI:10.1093/ee/16.5.1152

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

The effects of humidity, photoperiod, and length of the period of cold exposure on overwintering of the spotted tentiform leafminer,Phyllonorycter blancardella, and its two braconid parasites,Pholetesor pediasandPholetesor ornigis, were studied in the laboratory and in the field. The length of the cold period required to terminate diapause was approximately 12 wk forP. blancardellaandP. pedias. Photoperiod did not affect the development or overwintering survival of either species.P. ornigisshowed little response to the length of the cold period but did not develop as quickly when reared at short photoperiods as at long photoperiods. Postdiapause development of the three species was significantly faster and survival was greater at 98% RH than at the lowest humidity (19% RH). Degree-day models were found to predict dates of 50% emergence in the field within 6 d forP. blancardella, 6–10 d forP. ornigis, and 2–4 d forP. pedias. Spring emergence of both species of parasites was well synchronized with the preferred stages (instars 1–3) of their host. Reasons for the success ofP. pediasin the overwintering (fall) and spring generations are discussed.

ISSN:0046-225X    

DOI:10.1093/ee/16.5.1157

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Greenbugs,Schizaphis graminum(Rondani), of biotypes Band E were studied on three wheat genotypes: ‘TAM 105’, susceptible to both biotypes; ‘TAM 107’, “broken resistance” to biotype E but resistant to biotype B; and ‘Largo × TAM 105’, “broken resistance” to biotype B but resistant to biotype E. “Broken resistance” describes a plant genotype resistant to most biotypes but with reduced resistance to one or more biotypes. All combinations of aphid biotype and plant genotype were tested by observing feeding behavior, fecundity and plant damage. Electronic feeding monitors were used for 12 h, after which aphids were reared on the same leaf to obtain data on fecundity and damage. Greenbug biotypes Band E fed less successfully on their respective resistant genotypes than on ‘TAM 105’. The successful or adapted greenbug on a genotype exhibited less baseline and salivation time, a lower number of probes and x-waves, but more phloem ingestion time than the less adapted one. A successful greenbug also produced more offspring and heavier insects, produced less honeydew per one unit of greenbug dry weight gained, and caused a greater reduction in leaf chlorophyll. The broken resistances were variable in all the experiments, but responses were generally intermediate between the susceptible and resistant genotypes, which we interpreted as indicating that they still have some degree of resistance.

ISSN:0046-225X    

DOI:10.1093/ee/16.5.1163

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

A three-dimensional trajectory forecast model was used to correlate synopticscale weather patterns with the first spring appearance of the green cloverworm (GCW),Plathypena scabra(F.), moth in central Iowa. The feasibility of wind-aided migration was studied, and a comparison of outbreak and endemic years was made. The first appearance of the GCW, as determined by catches in blacklight traps and larval surveys in each year studied (1976–85), occurred during periods of sustained southerly wind flow from the suspected overwintering region. Outbreak years had more days suitable for migration than endemic years. GCW migratory behavior and atmospheric transport are proposed as the mechanism by which the GCW reaches Iowa.

ISSN:0046-225X    

DOI:10.1093/ee/16.5.1169

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Eight treatment combinations of insecticides and winter and summer annual weed herbicides were applied to alfalfa plots to investigate the impact of weed management practices and insecticide use on density and intensity of populations of the potato leafhopper (PLH),Empoasca fabae(Harris). PLH nymph and adult populations were monitored during the growth seasons of 1983–85. Adult population densities (PLH per m2) and intensities (PLH per stem and PLH per gram of alfalfa) were lower in plots receiving treatments for control of winter annual weeds (grass-infested alfalfa) and were higher in plots treated with both winter and summer annual weed controls (weed-free plots). Weed control measures were not a significant influence on population densities and intensities of PLH nymphs. Where insecticides were applied, neither nymph nor adult abundance and intensity were affected by weed-control treatments. Nymph and adult density varied within alfalfa growth periods and between seasons. Nymphs were more abundant during the second growth period, whereas adults reached their peak density during the third alfalfa growth period. Therefore, field scouting to determine PLH populations should be intensified during these periods.

ISSN:0046-225X    

DOI:10.1093/ee/16.5.1175

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Larval weights and leaf-area consumption for the fall armyworm (FAW),Spodoptera frugiperda(J. E. Smith), were significantly reduced by feeding on resistant corn genotypes. Parasitism of FAW byCampoletis sonorensis(Cameron) resulted in further reductions in FAW weights and leaf-area consumption. Differences in parasitoid pupation, pupal weight, and time to adult emergence were not significantly affected by host FAW feeding on the resistant corn genotypes.

ISSN:0046-225X    

DOI:10.1093/ee/16.5.1181

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

The influence of female moth/pheromone-trap competition in shaping temporal patterns of catches ofArgyrotaenia citranawas studied in a series of experiments conducted within a semienclosed courtyard on the campus of Oregon State University. Three distinct periods existed in relation to the catch of males in traps; the catch of males by caged female moths; and the estimated frequency of mating of females. In the first period, when male emergence precedes female emergence, few males were attracted to females, few females were mated, and the trap's catch efficiency was high. During the second period when emergence of males and females was more equal, the attraction of male moths to females increased and mating peaked. However, the pheromone trap's catch was similar or lower than during the first period. In the third period when male emergence was considerably less than female emergence, attraction of males to females and mating decreased sharply, while the trap's catch increased again and showed a small second peak. When high immigration rates of males were simulated results were similar, except that the second catch peak was much larger. Overall, competition between the pheromone trap and female moths appeared to be regulated by protandry and the cessation of calling by mated females, while mated males continued to respond to pheromone sources. Immigration and differential survivorship of males and females may account for the timing and magnitude of the second peak observed in the pheromone trap's catch.

ISSN:0046-225X    

DOI:10.1093/ee/16.5.1185

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

The distribution of western corn rootworm,Diabrotica virgifera virgifera, larvae in corn roots was mapped through the larval period in three different plantings of corn in 1984 and 1985. Roots were boiled in a solution of lactophenol and acid fuchsin to fix and stain the larvae. First instars were found in the seminal roots as well as roots on the first five whorls. Significantly more first and second instars were oriented toward the root tip than the root base. Over time, larvae tended to move into the roots of the newer whorls. In separate laboratory experiments, cut and uncut corn roots were infested with first instars. Orientation of first instars in uncut roots was similar to that seen in the field. Removing the root tips 1 h before or 24 h after infestation resulted in an equal number of larvae orienting toward and away from the root terminus, whereas tip removal 24 h before infestation resulted in more first instars orienting toward the root base.

ISSN:0046-225X    

DOI:10.1093/ee/16.5.1193

出版商:Oxford University Press    

年代:1987

数据来源: OUP

摘要:

Color attraction and flight behavior of Colorado potato beetle (CPB),Leptinotarsa decemlineata(Say), were investigated using window flight traps placed in a potato field. CPB were attracted to yellow traps with peak wavelength reflectance between 550 and 580 nm. Similar peak reflectance was recorded for potato leaf material. There was evidence that red, with peak reflectance at 680 nm, and black, with low uniform reflectance, were avoided by CPB. The approximate 50:50 sex ratio of trapped CPB remained constant throughout the growing season. Trap color did not influence sex ratio. Greatest flight activity occurred after emergence of first-generation adults, when host plant material was scarce. There was a significant positive relationship between temperature and CPB catches. There were no significant differences in magnitude of catches between the 0800–1200 and 1200–1600 hour time periods.

ISSN:0046-225X    

DOI:10.1093/ee/16.5.1199

出版商:Oxford University Press    

年代:1987

数据来源: OUP