摘要:

The Mediterranean fruit fly,Ceratitis capitata(Wiedemann), showed a distinct preference for a dry habitat (180 cm/yr rainfall) on the island of Oahu, but they were persistent in dry areas, particularly Makaha Valley. The mean infestation rate was 0.21 and 33.5 flies per kilogram of coffee in wet and dry areas. Dissection of coffee collected in the field showed that larval recoveries per 100 fruits were equal in wet and dry areas, but larval mortality was statistically higher in wet areas; the larvae apparently die from decay of the fruit, especially if they crack open. We conclude thatC. capitataandDacus dorsalisHendel distribution and abundance are directly affected by the elimination of preferred host fruits and indirectly by climate causing differential effects on their survival in coffee and other fruits in wet versus dry areas.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1042

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

I investigated the effects of noncatastrophic control technologies that alter life history parameters (such as the use of resistant plant varieties) on the growth of insect populations. I used a computer model to simulate population dynamics of the flat grain beetle,Cryptolestes pusillus(Schönherr). The effects of increasing duration of larval development (by 5, 10, 15, or 20 d) or decreasing fecundity or larval survival (by 25, 50, or 75%) on population growth were simulated. Growth curves for populations with reductions in fecundity or larval survival were nearly identical. The effects of decreasing fecundity or larval survival were apparent during the first generation, whereas the effects of increasing duration of larval development did not become apparent until the second generation. Altering any of the life history parameters resulted in as much as 99% reduction in population levels at constant temperatures and as much as 87% reduction in population levels at actual temperatures in a grain bin. The results indicate that use of control technologies that cause even a small change in a life history parameter may have a significant effect on population growth when applied over a growing or storage season. The combination of such technologies with other methods of control may improve the cost effectiveness of pest management techniques, even if the noncatastrophic control techniques do not provide adequate control when used alone.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1050

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Bembidion quadrimaculatumL. is one of the most common carabids in Michigan onion fields and feeds on onion maggot,Delia antiqua(Meigen), eggs and first instars as well as a number of other prey. Laboratory and field experiments were conducted to determine the effectiveness ofB. quadrimaculatumas a predator of the onion maggot. Up to 25 onion maggot eggs per day were consumed perB. quadrimaculatumadult. Consumption of eggs and first instars increased with temperature. Predation was higher when eggs were placed on the soil surface than for eggs placed 1 cm deep (70% versus 17.5%). In field cage studies,B. quadrimaculatumreduced onion maggot numbers by up to 57%.B. quadrimaculatummay therefore be an important biological control agent for the onion maggot.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1056

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

The effect of increased densities on mortality and fecundity ofTyrophagus putrescentiae(Schrank) adults was studied with a yeast granule as the food source. Contest competition operated when adult stages competed for the yeast granule (the slope had abvalue of 0.1). Survival of females exceeded that of males under crowded conditions. The oviposition rate of the females decreased with density. Density and consumption time were curvilinearly related, suggesting that the effect on mortality and fecundity was caused by the mites competing for feeding space on the yeast granule.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1060

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Two adelgids,Pineus boerneriAnnand andP. coloradensis(Gillette), are serious pests of red pine,Pinus resinosaAiton, in parts of New England. Both species are parthenogenetic, trivoltine, and complete six stages of development. The life stages were readily distinguished from one another within and between species by body size and by several morphological features including antennae, setae, and wax-producing glands. Generation overlap was so pronounced that all life stages of these adelgids were present nearly all times during the year.Pineus boerneri, an introduced species, spread at an average rate of 15 km per year during a 5-yr period between surveys. It invaded 21 of the 48 red pine stands sampled in Connecticut and Massachusetts, which is south of the natural range ofP. resinosa, and injured and killed trees at all of the inhabited sites.P. coloradensis, a native and heretofore innocuous species, occurred in all 10 stands sampled in New Hampshire and Vermont, which is within the natural range ofP. resinosa, and in 35 of the 48 plantations located in Connecticut and Massachusetts. Surprisingly, it injured and killed trees in more than 40% of these stands in both areas.Population trends of these adelgids during a 5-yr period indicated thatP. boernerihad displacedP. coloradensisin all 3 previously cohabited pine stands and in 7 of 12 others whereP. coloradensisinitially had occurred alone and whereP. boerneriinvaded subsequently. In four of the five remaining stands in the latter category,P. coloradensishad been reduced to very low density. These results reaffirm the superior competitive ability ofP. boerneridemonstrated in laboratory experiments.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1066

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Development (d), reproduction (Md), and intrinsic rate of increase (rm)for greenbug,Schizaphis graminum(Rondani), biotypes E, F, G, and H were observed on 13 small grain and sorghum entries, including five sources of resistance to biotype E (GBE). Thedwas expected to increase, whereasMdandrmwere expected to decrease for each biotype on resistant plants. However, thedandMdvalues for each biotype did not correlate as well asrmto the resistance status of the cultivar. In general, thed,Md, andrmvalues for biotype E were better than comparable values for biotypes F, G, and H. Biotype E also equaled or outperformed the biotypes on most of the biotype E-resistant cultivars except ‘Insave F.A.’ rye. The lowrm's for GBF, GBG, and GBH compared with GBE provide some insight as to why these biotypes are rare in wheat and probably would not reach damaging infestation levels. GBE is currently the predominant biotype by virtue of its broader host range and resistance breaking ability, plus the most fit as measured by the superiorrm's. Therefore, there does not appear to be a cost for virulence in this greenbug biotype. The displacement of biotype E by the other biotypes does not seem likely, based on our results.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1074

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Distribution of the melon fly,Dacus cucurbitaeCoquillett, was determined by trapping males at 100 sites throughout the island of Rota, Commonwealth of the Northern Mariana Islands. Melon flies were most numerous along the south coastal trap sites. Flies caught in traps were significantly correlated to pupal yield from samples of infested fruits ofMomordica charantiaL. for two of three years. Rainfall was significantly correlated with trap catches for the two low rainfall years of 1984 and 1987, but not for the two high rainfall years of 1985 and 1986. The highest trap catch of 5.8 flies per trap per day in 1986 was 100 times less than the number of flies caught in an earlier study in 1961 when the peak was 614 flies per trap per day and precipitated eradication efforts in 1963.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1079

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

The influence of five cucurbit hosts on survival, developmental time, and adult weight of the squash bug,Anasa tristis(De Geer), was determined. Percentage survival from egg to adult was significantly affected by host. Survival to the adult stage on the five hosts was highest on pumpkin,Cucurbita pepoL. var.pepo(70.0%), followed by squash,Cucurbita pepoL. var.melopepo(49.0%); watermelon,Citrullus lanatus(Thunb.) Matsum.&Nakai (14.4%); cucumber,Cucumis sativusL. (0.3%); and muskmelon,Cucumis meloL. (0%). Host type had a significant effect on developmental time to third and fifth instar and to adult, with a longer developmental time on watermelon. The adult sex ratio was 1:1. Adult females were significantly heavier than males. Greater adult weights for both males and females resulted when insects developed on squash. However, the effect of host on adult weight was significant only for males.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1083

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

Daily per capita birth rates of the cabbage aphid,Brevicoryne brassicae(L.), increased 40–50% as numbers of adult female aphids in artificially created groups on kale plants increased from three or fewer to six or more adults. Reproduction was enhanced at a declining rate such that the maximal effect was observed at 10 females per group, with no further increase up to 27 females per group. Increasing the number of females per group enhanced per capita birth rates on potted kale plants under greenhouse conditions and on field-grown kale plants. Enhancement under field conditions was observed in warm (22°C) but not cool (15°C) periods.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1086

出版商:Oxford University Press    

年代:1989

数据来源: OUP

摘要:

The influence of tethered flight and carbohydrate deprivation on soybean looper,Pseudoplusia includens(Walker), whole-body lipids, oviposition rate, and survivorship was examined using a factorial experimental design. Carbohydrate deprivation had a greater effect than flight on all three variables, although flight decreased fecundity. Moths that were subjected to only one stress (2 h of daily flight or provided water as their only food source) were significantly different from the no-stress group (nonflown and fed) and those that were starved and flown. The general trend apparent for all parameters was nonflown-fed ≥ flown-fed ∼ nonflown-starved ≥ flown-starved, except for stored lipids that showed no statistical difference between flown-starved and nonflown-starved moths. Average longevity ranged from 9 d for nonflown-fed moths to 6 d for flown-starved moths. These data demonstrated that the availability of a nectar source may be an important factor in the success of long-distance soybean looper dispersal and subsequent reproduction.

ISSN:0046-225X    

DOI:10.1093/ee/18.6.1090

出版商:Oxford University Press    

年代:1989

数据来源: OUP