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11.
Alfalfa weevils (Hypera postica (Gyllenhal)) with vestigial hind wings were discovered in a population from Wageningen, the Netherlands, and two populations from the United States—an eastern weevil strain from Beltsville, Maryland and an Egyptian weevil strain from Atascadero, California. Such a mutant was absent from 23 other populations surveyed in the United States—three from eastern, seven from western, and 13 from Egyptian weevil strains. This mutation is due to a dominant autosomal gene with normal-wing individuals as recessive. The mutant gene can be transferred from eastern weevil to the western weevil strain. The short-wing trait may be useful for genetic manipulation to control the alfalfa weevil.
Résumé Des H. postica aux ailes postérieures vestigiales ont été découverts dans une population de Wageningen (Pays Bas) et deux des USA—une lignée orientale de Beltsville (Maryland) et une lignée de H. brunneipennis d'Atascadero (Californie). Ce mutant était absent de 23 autres populations examinées aux USA: 3 de l'est, 7 de l'ouest et 13 de H. brunneipennis. Cette mutation est due à un gène dominant antosomal avec aile normale comme récessif. Le gêne mutant peut être transféré des lignées orientales aux lignées occidentales. Le caractère aile courte peut être pratique pour les manipulations génétiques destinées à maîtriser les populations d'H. postica.相似文献
12.
In field experiments, larvae of codling moth Cydia pomonella (L.) rarely acquired granulosis virus on hatching from the egg, but picked up most later, on the tree surface. Deposits of virus sprayed in 1.0% w/v skimmed milk did not affect neonate larval behaviour. Larvae died, usually in the first instar, after entering treated fruit, but they frequently entered via the calyx or near the base of the stalk or through cracks in the skin, where little feeding damage by first-and sometimes second-instar larvae was seen.
Résumé En verger, la pulvérisation d'oeufs de carpocapse avec du virus de la granulose en suspension dans l'eau (additionnée de lait écrémé dilué à 1%) n'a pas modifié la survie des chenilles avant pénétration dans le fruit; par contre la pulvérisation des arbres a provoqué une forte mortalité. Bien que des chenilles consommant des poils et la surface des feuilles aient été observées avant leur pénétration dans le fruit, ce qui aurait pu provoquer leur contamination par le virus, il semble que la contamination létale provienne des fruits seuls.La présence de produit n'a modifié ni le comportement larvaire, ni le taux de pénétration dans les fruits; la mortalité y a lieu ensuite, généralement au premier stade. Dans 74 à 78% des cas, les chenilles ont pénétré dans le fruit par le calice ou près de la base du pédoncule — aucun dégât provenant de larves du premier stade n'y était visible, de même que dans le calice pour les larves du deuxième stade. Par contre, toute pénétration par la surface du fruit était repérable dès le premier stade. Il est possible que la répartition des lieux de pénétration dans le fruit influe sur la létalité due au virus et explique les variations d'efficacité observées en verger. Un système de classification des dégâts, provoqués lors de la pénétration dans le fruit, de chenilles du premier au troisième stade est proposé pour évaluer l'efficacité des essais en verger.相似文献
13.
David I. Dunstan Keith E. Turner Wayne R. Lazaroff 《Plant Cell, Tissue and Organ Culture》1985,4(1):55-60
The quality of shoots in cultures of the apple rootstock, M4, was used as a criterion for the selection of an optimum medium.
The frequency of shoots in defined shoot clases was monitored for each of five media, which differed in the type and concentration
of phytohormone. Media containing BA (1.15 mg l-1) and IBA (either 0.15 or 0.20 mg l-1) produced the maximum number of shoots that were desirable for transplantation and acclimatization. 相似文献
14.
The palm weevil, Rhynchophorus palmarum (L.), was collected in cocoons from red ring-diseased coconut palms (Cocos nucifera L.) in Trinidad and Tobago. Juveniles of five species of nematodes were extracted from the genitalia and macerated bodies of newly emerged adults of the palm weevil: Rhadinaphelenchus cocophilus (Cobb) Goodey (the red ring nematode), Teratorhabditis sp., Diplogasteritus sp., Mononchoides sp., and Bursaphelenchus sp. Over 90% of newly emerged weevil females and males were infested internally with red ring nematode juveniles, and over 47% of the weevils contained more than 1,000 red ring nematodes each. There was no significant correlation between weevil body length and the number of red ring nematodes carried internally by each weevil. Teratorhabditis sp. and Diplogasteritus sp. were extracted from over 50% of the palm weevils, and Monochoides sp. and Bursaphelenchus sp. were found in a small proportion of the weevils. Field-collected adult weevils were also internally and externally infested with a Rhabditis sp., which was not observed in or on weevils allowed to emerge from field-collected cocoons. 相似文献
15.
Storage of apple fruits ( Pyrus malus L. cv. Golden Delicious) at different temperatures (0, 12 and 35°C) markedly altered the pattern of water freezing in the seeds. Higher temperatures of storage brought about a shift from the sequential to the discontinuous type of freezing in seeds, the low temperature exotherm (LTE) being much more pronounced than the high temperature one (HTE). The occurrence of LTE was highly correlated with embryo death. Fruit storage at higher temperatures also caused a decrease in the threshold super cooling temperature of seeds and of naked embryos, removed from the seed coat and endosperm. The decrease was less pronounced in naked embryos than in intact seeds. The results presented show that the frost resistance of apple seeds relies mainly on the supercooling ability of the embryos and is increased by the presence of seed coat and endosperm. The broad peak of the LTE indicates that, in contrast with other seeds and many super cooling organs, massive ice nucleation in apple seeds occurs within the embryo tissues and that extra organ freezing seems to be of less importance. Therefore, the increased super cooling ability of apple seeds, isolated from fruits stored at higher temperatures, seems to rely on those seed properties that protect embryo cells against heterogeneous ice nucleation. 相似文献
16.
Harry Jan Swartz Robert Bors Fouad Mohamed S. Kristine Naess 《Plant Cell, Tissue and Organ Culture》1990,21(2):179-184
Shoot regeneration from Rubus leaves was obtained on a medium containing MS salts, vitamins and sugars, Staba vitamins, casein hydrolysate (100 mg l–1) and 10 M thidiazuron. Shoot regeneration from Malus leaves was obtained on N6 rice anther medium with 5 M thidiazuron. In vitro pretreatment of source shoots with either colchicine or thidiazuron enhanced the organogenic potential of detached leaves of two Rubus hybrids. The response to colchicine was quadratic and occurred at non-mutagenic concentrations (75–250 M). The response to thidiazuron was exponential between 0 and 5 M. When applied as a pretreatment, the effectiveness of several different cytokinins (benzyladenine, thidiazuron, zeatin) at enhancing Malus and Rubus organogenesis was related to the shoot proliferation activity of the cytokinin and to treatment-induced variation in leaf and petiole size.Abbreviations BA
benzyladenine
- 2,4-D
2,4-dichlorophenoxyacetic acid
- IBA
indolebutyric acid
- MS
Murashige & Skoog basal medium devoid of plant growth regulators
- OI
organogenesis-initiating subculture
- PTI
colchicine pretreatment subculture
- PTII
cytokinin pretreatment subculture
- NAA
naphthaleneacetic acid
- TDZ
thidiazuron
- zeatin
trans-zeatin 相似文献
17.
R. C. H. Shepherd 《BioControl》1990,35(4):583-587
Host specificity tests carried out in the laboratory in Australia during 1977, showed thatMicrothrix inconspicuella Ragonot could develop on young apple leaves (Harley
et al., 1979). Field studies in unsprayed apple orchards in South Africa showed that some feeding occurred, but fewer than 40% of
late instar larvae developed to adults when confined in sleeves on apple tree branches. No feeding or survival occurred in
large field cages or in the open. Adults which developed from apple fed larvae were smaller, deformed, occasionally mated
and laid fertile eggs but their progeny did not feed or develop on apple fruit or leaves. In conclusion,M. inconspicuella larvae did not develop on apple fruit or leaves in the field, damage was mainly limited to apples already injured and feeding
on leaves was minimal. Under normal pest control practicesM. inconspicuella populations did not survive on any part of the apple tree or onE. australis growing under the trees.
相似文献
18.
Rosamond C. H. Shepherd 《BioControl》1990,35(3):441-447
Host specificity tests of the moth,Microthrix inconspicuella Ragonot in Australia, indicated that larvae could feed and develop on young apple leaves. Additional tests in South Africa
on leaves and fruit of the 4 apple varieties, Jonathan, Starking (Red Delicious), Granny Smith and Golden Delicious, showed
that apples were not a preferred food. Little feeding occurred and pupation happened infrequently. No 2nd generation resulted whenM. inconspicuella colonies were confined on apple fruit or leaves.
相似文献
19.
Aerial dispersal of European red mite, Panonychus ulmi (Koch), in commercial apple orchards was estimated by trapping windborne mites. Studies were conducted at four orchards in eastern New York during 1989 and 1990 and at three orchards in western New York during 1989. In each orchard mites were trapped in three locations; the interior of the orchard, at the border of the orchard and in a field or woodlot beyond the orchard. Large numbers of mites were captured, even when the numbers of mites on apple foliage were well below levels where mite injury to leaves was visible (less than five per leaf). The log numbers of mites trapped were linearly related to the log density of mites on leaves and this relationship was consistent for each year and region the study was conducted. The trap captures among the three locations in and outside an orchard were highly correlated. The implications these findings may have on metapopulation dynamics and resistance to acaricide dynamics are discussed. 相似文献
20.
The induction of parthenocarpic fruit set was investigated using the apple cvs. Golden Delicious and Jonagold. The gibberellins GA3, GA4, GA5 and GA7 and the synthetic phenylurea-type cytokinin CPPU (N-(2-chloro-4-pyridyl)-N-phenylurea), were applied alone and in combination to unpollinated flowers at the end of petal fall. Gibberellins induced only a marginal final set of parthenocarpic fruits. CPPU sprays were more effective, particularly in the first year. When applied in combination, CPPU and gibberellins had a positive synergistic effect on parthenocarpic fruit set and fruit size, but a negative effect on flower induction the next year. After CPPU + GA sprays, percent fruit set was similar, or greater, compared to natural pollinated trees. The parthenocarpic fruits induced by CPPU + GA had an increased length to diameter ratio. CPPU stimulated, and GA4 and GA7 reduced, the russeting of the parthenocarpic fruits. The internal quality of the fruits was hardly affected, but Ca-deficiency symptoms occurred more frequently in parthenocarpic fruits. 相似文献