摘要:

In the 1st of 3 stages of cocoon spinning,Campoletis sonorensis(Cameron) spun the loosely meshed outer layer of the cocoon. The 2nd stage began when the parasitoid initiated construction of the more closely woven inner layer. During the 3rd stage of spinning, the inner layer was lined with a thin, translucent sheet of silk.C. sonorensiswere generally incapable of repeating spinning operations when removed at various stages of spinning; only those which had been removed from half completed or completed outer layers were able to spin a normal cocoon. Cocoon spinning was affected by the moisture content of the spinning substrate, but not by atmospheric moisture.

ISSN:1754-5692    

DOI:10.1093/ee/3.4.714

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Resistance in maize to 1st-generation European corn borer larvae,Ostrinia nubilalis(Hübner), is partly due to the antibiotic nature of 2,4-dihydroxy-7-methoxy-benzoxazin-3-one (DIMBOA). Larval bioassays (Klun et al. 1967) showed that DIMBOA and not its degradation product, MBOA, is the active agent in resistance. Normal larval development is inhibited and larval mortality increased by DIMBOA. A diallel analysis of 11 inbred maize lines by Klun et al. (1970) demonstrated highly significant correlations between DIMBOA concentration and leaf feeding resistance for inbreds and single crosses.

ISSN:1754-5692    

DOI:10.1093/ee/3.4.718

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

‘Gaucho’ (CI 15323) is an octoploidTriticaledeveloped from a cross between susceptible ‘Chinese Spring’ common wheat and an Argentine rye (Insave F. A.) that is resistant to the greenbug,Schizaphis graminum(Rondani). (Insave F. A. is the only greenbug-resistant rye known at present.) Arriaga and Ree (1963) reported that a single dominant gene controlled the overall resistance in this rye to the greenbug. The transfer of resistance to common wheat would be of great importance to wheat production since no practical level of resistance is present in commercial varieties. However, the chromosomes of rye rarely pair with those of wheat in the intergeneric hybrid, so the transfer of desirable characteristics from rye to wheat by conventional breeding methods is impossible (Riley and Chapman 1958). However, a number of workers have used an irradiation technique to obtain transfer of genetic material carrying genes for disease resistance via alien chromosomes to wheat (Sears 1967). Therefore, the transfer of greenbug resistance from the Argentine rye via Gaucho to wheat should be possible since only one of the pairs of rye chromosomes bears the genes for resistance.

ISSN:1754-5692    

DOI:10.1093/ee/3.4.720

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Most of the economically important genera of North American Scolytidae commonly infest trees weakened by a variety of agents including drought, natural disasters, diseases, or old age, and are therefore considered secondary insects (Rudinsky 1962). Outbreaks of defoliating insects have occasionally weakened trees to the point they have become susceptible to secondary bark beetle invasion. For example, secondary bark beetles killed 16.7% of the ponderosa pine (Pinus ponderosaLaws.) defoliated by the pine butterfly,Neophasia menapiaFelder&Felder, in central Idaho (Evenden 1940). Similarly, defoliation of white fir,Abies concolor(Lindl.), by the Douglas-fir tussock moth,Orgyia pseudotsugataMcDunnough, in California was followed by infestations of the fir engraver,Scolytus ventralisLeConte, and a roundheaded borer,Tetropium abietisFall (Wickman 1963). Unfortunately, the intensity of defoliation associated with such bark beetle outbreaks has seldom been documented and as a result we lack information on the degree of defoliation likely to render trees susceptible to bark beetle attack.

ISSN:1754-5692    

DOI:10.1093/ee/3.4.722

出版商:Oxford University Press    

年代:1974

数据来源: OUP

摘要:

Foliar treatments with methomyl appear to be promising (Coppedge et al. 1972, McGarr et al. 1972) as a method of controlling certain lepidopteran pests of cotton including the bollworm,Heliothis zea(Boddie), and even the tobacco budworm,Heliothis virescens(F.). This latter insect pest has become increasingly difficult to manage in certain areas due to the development of resistance to organophosphorus and other insecticides (Adkisson 1969).

ISSN:1754-5692    

DOI:10.1093/ee/3.4.723

出版商:Oxford University Press    

年代:1974

数据来源: OUP