摘要:

After an initial application of chemical insecticides, all field plots of fall lettuce treated with nuclear polyhedrosis viruses isolated fromTrichoplusia ni(Hüibner) andAutographa californicaSpeyer, or with a commercial preparation of strain HD-l,Bacillus thuringiensisvar. Kurstaki (3A,3B) DeBarjac, demonstrated adequate control of lepidopterous larvae. However, damage by thrips was excessive and decreased the quality of the crop. OfT. nilarvae collected from untreated plots, 28% were parasitized; no more than 1.1% of theT. niandSpodoptera exigua(Hübner) larvae collected from lettuce treated with chemical insecticides were parasitized; and 5.2–15.4% of those collected from plots treated with microbial insecticides were parasitized. Survival to pupation of larvae of both species was highest among those collected from the chemically-treated fields and from plots treated with HD-l and lowest among those collected from plots treated with the nuclear polyhedrosis viruses. The microbial insecticides therefore have a potential as control agents for lepidopterous pests, chemical pesticides have a severe effect on parasites, and the microbial insecticides have a deleterious effect on parasitism that may limit control by a combination of pathogens and parasites.

ISSN:1754-5692    

DOI:10.1093/ee/1.6.780

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

Field releases ofTrichogramma pretiosumRiley from Brownsville, Texas, were ineffective against either natural, supplemental, or artificially applied egg populations ofTrichoplusia ni(Hübner) andPieris rapae(L.) on cabbage at Columbia, Missouri. Releases ofTrichogramma evanescensWestwood on this crop at Columbia were highly effective againstP. rapae, but only partially effective againstT. ni. Artificially applicd eggs ofT. niandP. rapaewere highly parasitized byTrichogrammaspp., but many of these applied eggs collapsed prior to complete parasite development.

ISSN:1754-5692    

DOI:10.1093/ee/1.6.785

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

Probably the most effective method of pest management in cotton in the western United States is the strip cutting of alfalfa adjacent to cotton described by Stern et al. (1967). When a stand of alfalfa is maintained in uneven growth stages, the lygus bugs (Lygusspp.), mainlyL. hesperusKnight, that prefer the alfalfa are retained in the alfalfa where they do little if any harm and do not migrate to the cotton. Fye (1971) described a system in which populations of insect predators increased by feeding on Biotype C of the greenbug,Schizaphis graminum(Rondani), in grain sorghum and then migrated to adjacent cotton as the grain sorghum matured. Thus, a strong potential for development of large populations of predators was evident. The study reported here was made primarily to determine the distance such predators might move, and secondly to determine the effect of the timing of the plantings of the 2 crops involved in the interchange.

ISSN:1754-5692    

DOI:10.1093/ee/1.6.790

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

When the behavior of released nocturnally active insects, especially moths, is to be studied, they must be retained in the holding cage until the desired hour. Premature escape, as in daylight, can result in high mortality from predators; for example, at the laboratory on St. Croix more than 50% of small moths released in daylight are probably lost to predators, principally the gray kingbird and the anole lizard. Also, in studies using female pheromone, if the released male moths are not responsive to pheromone until late at night, as was the cabbage lopper,Trichoplusia ni(Hubner) (Shorey and Gaston 1965), early releases can result in poor recovery in nearby pheromone-baited traps. For both reasons, during our tests on St. Croix, we wished to delay the release of cabbage lopper males until around midnight. To avoid working at inconvenient hours and to reduce our reliance on cooperators who would have to open cages located at distant sites, we designed a device to open holding cages automatically.

ISSN:1754-5692    

DOI:10.1093/ee/1.6.791

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

One of the most interesting behavioral traits of the gypsy moth.Porthetria dispar(L.). is the diel periodicity exhibited by the late instars. During the 1st 3 stadia, the larvae remain in the tree crown and feed normally in the morning hours (Leonard 1970). However, sometime near the beginning of the 4th stadium, a change in behavior of the larvae occurs; they feed during the scotophase and rest in protected places during the photophase.

ISSN:1754-5692    

DOI:10.1093/ee/1.6.793

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

Moisture stress has been suggested as a factor predisposing cotton (Leigh 1963) and grape (Flaherty et al. 1969) to attack by spider mites. The most damaging spider mite occurring on grapes,Tetranychus pacificusMcGregor, is known to reach its highest densities on distal foliage exposed to direct sunlight (Flaherty and Huffaker 1970, Kinn and Doutt 1972a), where humidity is lowest and temperatures highest (Andres 1957). It has also been claimed that spider mite populations can be reduced by irrigating with overhead sprinklers (Flaherty and Huffaker 1970). Flaherty et a1. (1971) state spider mites are drowned and removed from foliage by washing with water. Studies undertaken in North Coast vineyards during the last 2 years indicate that sprinkler irrigation can be utilized in an integrated approach to spider mite control on premium wine varieties.

ISSN:1754-5692    

DOI:10.1093/ee/1.6.795

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

Scaphytopius nitridus(DeLong) is a leafhopper that is common in southern California citrus during June, September, and October, though it may be found at other times. I have observed it feeding on the midrib veins of citrus leaves and on the tender stem tissue. However, any feeding or mechanical injury is not apparent. When the insect was collected from citrus in 1970 and 1971 for use in vector tests of stubborn disease (Kaloostian and Pierce 1972), the specimens showed a high degree of parasitization by a pipunculid. Therefore, the adults and puparia were recovered from cottonorgandy sleeve and acrylic leaf cages and sent for identification to D. Elmo Hardy, University of Hawaii. He identified the species asTomasvaryella appendipes(Cresson) and noted (personal communication) thatT. appendipeshad not previously been recorded fromS. nitridus. However, the species does attack several other Cicadellidae and is widely distributed in the southeastern, south-central, and southwestern United States (Hardy 1943).

ISSN:1754-5692    

DOI:10.1093/ee/1.6.796

出版商:Oxford University Press    

年代:1972

数据来源: OUP

摘要:

Studies of the biology of aphids (Aphididae) have shown that in the migrating (alate) form, many species react to color. Cartier (1965, 1966) found that the pea aphid,Acyrthosiphon pisum(Harris), and the potato aphid,Macrosiphum euphorbiae(Thomas), preferred emitted yellow and orange light to blue, green, and red light. Also, these same species showed consistently better growth when they were reared with 24 hr of light of these particular wavelengths. Other workers reported the attraction of several species of alate aphids to yellow or orange surfaces (Broadbent 1948, Moericke 1951, Kennedy and Stroyan 1959, Kring 1967), and Moericke (1955, 1969) found that some may be attracted by yellow-white surfaces with strong UV radiation. Nevertheless, actual field tests in which the color responses of aphids have been used for control have been limited. Smith et al. (1964) and Kring (1964, 1970) found that aphids may be repelled from plants surrounded by aluminum foil (strongly light-reflective).

ISSN:1754-5692    

DOI:10.1093/ee/1.6.797

出版商:Oxford University Press    

年代:1972

数据来源: OUP

ISSN:1754-5692    

DOI:10.1093/ee/1.6.799

出版商:Oxford University Press    

年代:1972

数据来源: OUP