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1.
The interspecific associations amongAphis gossypii Glover (Aphididae: Homoptera),Menochilus sexmaculatus (Fabricius) (Coccinellidae: Coleoptera) andCamponotus compressus Fabricius (Formicidae: Hymenoptera) were studied in an unsprayed guava ecosystem under natural conditions. The predator(M. sexmaculatus) and the ant (Ccompressus) were positively associated with the aphid(A. gossypii), while a negative association was recorded between the predator and the ant. For quantifying these associations in terms of overlapping and exclusion, spatial interspecific association analysis was carried out. Between aphid and predator, and aphid and ant, partial overlapping (γ = 0.44 and γ = 0.55, respectively) was obtained. Thus, although the association between aphid and predator was positive, it did not seem to be strong. Between the aphid and ant it was suggestive of mutualism, without obligate interdependence. Moreover, the predator and ant showed a tendency to independent occurrence with respect to the aphid when the spatial correlations were calculated. The predator and ant showed spatially almost complete exclusion. 相似文献
2.
The response of three soft scales: the pyriform scale —Protopulvinaria pyriformis (Cockerell), the mango shield scale —Protopulvinaria mangiferae (Green), and the capparis soft scale —Coccus capparidis (Green), to paiasitization by the parasiteMetaphycus swirskii Annecke & Mynhardt (Hymenoptera:Encyrtidae), was studied. Although the parasite was able to complete its development in any of these three host species, different rates of mortality of parasite immatures were recorded in the various hosts. Parasite mortality inP. pyriformis was due to egg encapsulation only and was higher in the field than under laboratory conditions (53.1%vs. 27.7%, respectively). InP. mangiferae a total of 55.4% mortality was observed, while inC. capparidis it reached only 14.0%, rendering the latter the most suitable of the three soft scales tested, for successful development ofM. swirskii. 相似文献
3.
Two entomophthoraceous species,Zoophthora radicans andEntomophthora planchoniana, were found on the yellow pecan aphid,Monellia costalis, shortly after it was introduced into Israel. This aphid is a new host forZ. radicans anywhere. The fungus was isolated in pure culture and artificially inoculated on three Dipteran species:Musca domestica, Drosophila melanogaster andCeratitis capitata, as well as on the HemipteranEmpoasca sp. from pecan. The identity ofZ. radicans and some new characters,e.g. the production of two kinds of rhizoids, are discussed. The possibility of usingM. domestica as a vector for artificial spread of the fungus, as a means of biological control of various insect pests, is advocated. 相似文献
4.
H. Podoler 《Phytoparasitica》1981,9(3):179-190
The effects of three variable temperature regimes (18–24, 24–29, and 29–35°C) on the responses of two species of the genusAphytis Howard (Hymenoptera: Aphelinidae), parasitic upon the California red scale, were studied, and a test to analyze parasite behavior was developed.Aphytis lingnanensis Compere was generally more efficient thanA. melinus DeBach; however, whereas a high temperature regime (29–35°C) had a negative effect on the responses ofA. lingnanensis, it improved those ofA. melinus. The two species distributed their eggs in clumps, but were able to respond to increasing host density by reducing the number of eggs laid per encounter. The combined effects of numerical, and functional responses of the two species on host population were considered, with special reference to the mechanism of competitive displacement. 相似文献
5.
A 1% concentration ofBacillus thuringiensis wettable power (containing 16,000 IU/mg), applied at a rate of 48,000 IU/cm2, killed 95% of 4th-instar larvae of the carob moth,Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae), after 66 h and 100% after 85 h of exposure in laboratory tests. The mortality caused by a 0.5% concentration (24,000 IU/cm2) was significantly lower and presumably inadequate for practical application against this pest. 相似文献
6.
D. Gerling 《Phytoparasitica》1984,12(2):109-118
Wild and cultivated plants in the vicinity of Kibbutz Nahshon and a few additional locations in Israel were sampled for the presence ofBemisia tabaci Genna-dius (Homoptera: Aleyrodidae). The whiteflies, together with their parasites,Eretmocerus mundus andEncarsia lutea, were found to develop on numerous host species throughout the winter. Especially high levels were reached onLan-tana camara, Abutilon grandifolium andIpomoea batatas. During late winter and spring the population on these hosts declined. From April onwards the populations increased on potatoes and sunflowers. 相似文献
7.
M. Wysoki 《Phytoparasitica》1979,7(2):101-106
A list is given of the beneficial insects introduced into Israel during 1971–1978 by the Institute of Plant Protection Quarantine Laboratory for biological control of plant pests. The list includes 15 species of Hymenoptera (14 parasites and one parasite/predator) as well as four coleopterous predators. Included are each shipment’s origin, date and sender, as well as the results of these introductions. 相似文献
8.
G. Jager H. Velvis 《European journal of plant pathology / European Foundation for Plant Pathology》1988,94(5):225-231
Experiments in the laboratory and on farms with potato tubers in storage are described in which sclerotia ofRhizoctonia solani were inactivated after inoculation of infected tubers with a suspension of conidia and hyphal fragments ofVerticillium biguttatum. Sclerotia on freshly harvested tubers can be killed in a period of six to eight weeks, provided that (1) a direct contact between sclerotia and conidia ofV. biguttatum is obtained, (2) the temperature during the storage period is at least 15 °C, but preferably closer to 20 °C during the first weeks, and (3) the relative humidity of the air between the tubers is at least 99%. Seed tubers are only certified as export quality if the infection withR. solani, visible as sclerotia on the tubers, is assessed as below a specified incidence. To restore the economical value of tubers with many sclerotia, living sclerotia can be inactivated byV. biguttatum. However, also dead sclerotia have to be removed, as dead and living sclerotia cannot be distinguished visually by inspectors. A satisfactory way to remove dead sclerotia from tubers has not yet been found. 相似文献
9.
The pathogenicity of steinernematid and heterorhabditid nematodes to caterpillars of the giant looper,Boarmia selenaria (Schiffermüller) (Lepidoptera: Geometridae), was determined under laboratory conditions. High mortality (over 80%) was achieved, in a petri dish bioassay, with a minimum of 20,000 infective juveniles (IJ) ofSteinernema carpocapsae (Filipjev) (=Neoaplectana carpocapsae Weiser), strain ‘All’. The LD50 was 4250 IJ per caterpillar. Similar results were obtained withS. carpocapsae, strain ‘Mexican’,Steinernema sp., strain ‘CR’;Heterorhabditis bacteriophora, strain ‘HP88’; andHeterorhabditis sp., strain ‘IS’. The first and second instars were the most susceptible stages to nematode infection. A laboratory model assay indicated that 80–90% of the caterpillars were killed when they migrated to the soil to pupate; this occurred when IJ were applied to sandy and heavy soils at a concentration of 400 IJ/cm3 soil. A greenhouse test reconfirmed the effectiveness of utilizing the entomopathogenic nematodes in an “ambush” system against caterpillars migrating to the soil. 相似文献
10.
The effect of azadirachtin and salannin, two triterpenoids isolated from seeds of neem (Azadirachta indica A. Juss), on the feeding response ofSpodoptera littoralis (Boisd.) andEarias insulana (Boisd.) larvae, was investigated. Styropor (foamed polystyrene) lamellae were painted on both sides with a mixture of 5% sucrose with different concentrations of either azadirachtin or salannin dissoled in methanol-water (3∶7). Azadirachtin strongly suppressed feeding inS. littoralis larvae even at 0.001%, whereas salannin showed some antifeedant activity at 0.005% and above. Larvae ofE. insulana were deterred from feeding on azadirachtin-treated lamellae even at 0.005%, whereas salannin was effective only at 0.01% and above. Azadirachtin applied on cotton leaves deterred larvae ofS. littoralis from feeding at all concentrations ranging between 0.001 and 0.02%. 相似文献
11.
Diflubenzuron was tested for its efficacy against the eggs and larvae ofEarias insulana Boisd. in laboratory experiments. The toxicity obtained on dipping the eggs was only moderate and, moreover, the results were highly inconsistent. The mortality of larvae on an artificial diet into which the wettable powder had been incorporated, was relatively high. 相似文献
12.
Six fungicides were evaluated under laboratory and field conditions for control of Phytophthora leaf blight of taro,Coloeasia esculenta, incited byPhytophthora colocasiae. Inin vitro tests Deraosan 65W was the most effective in inhibiting the mycelial growth of the test pathogen followed by Difolatan 80W, Fytolan (copper oxychloride), Apron 35F, Topsin-M 50W and Dithane Z-78 75W. Excellent control was obtained with Demosan 65W and Difolatan 80W, good control with Apron 35F, fair control with Fytolan, and poor control with Topsin-M 50W and Dithane Z-78 75W. Results ofin vivo tests were correlated with those of thein vitro tests. Roguing of infected leaves did not eradicate the pathogen but can only delay epiphytotics. 相似文献
13.
A quick and easy method for estimating the number of surviving nymphs of the tobacco whitefly (TWF),Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), after spray applications was developed in the laboratory. The method is based on the number of honeydew droplets ejected by TWF immatures during 30 minutes. Since the nymphs ofB. tabaci feed on the lower leaf surfaces, the honeydew excreted falls downward. In this study infested cotton leaves were placed with their lower side up, forcing the nymphs to eject the honeydew droplet upwards. Inverted plastic petri dish covers were placed over infested cotton leaves and after 30 minutes the droplets deposited on the inner side of each cover were counted and the average number of droplets per nymph was calculated. To estimate the number of live nymphs on an infested cotton leaf, the number of droplets ejected during 30 minutes was divided by the average number of droplets per nymph (factor of 1.23). 相似文献
14.
J. Halperin 《Phytoparasitica》1990,18(4):309-319
Fifty-four insect and four mite species are included in a list of the entomofauna of plane trees in Israel. Only two species are monophagous:Phyllonorycter platani (Stgr.) (Lepidoptera: Gracillariidae) andEdwardsiana iranicola Zachv. (Heteroptera: Cicadellidae). Four species are noxious:P. platani, the main insect pest of the plane trees in Israel;Zeuzera pyrina L. (Lepidoptera: Cossidae);Kalotermes flavicollis F. (Isoptera: Kalotermitidae); andE. iranicola. Of much lesser importance areTargionia vitis Sign. (Homoptera: Diaspididae),Heliothrips haemorrhoidalis Bché. andRetithrips syriacus May. (Thysanoptera: Thripidae). About half of the listed species are natural enemies and many are parasites ofP. platani. Details are given on the noxious species, together with recommendations for prevention and control. 相似文献
15.
16.
The effect of chocolate spot disease (incited byBotrytis fabae) on the host plant quality of two cultivars of faba beans (Vicia faba) for the black bean aphid (Aphis fabae), was investigated under greenhouse conditions. Faba bean cultivar Bolero is resistant to the aphid, whereas cv. Diana is susceptible. On healthy leaves of cv. Bolero, aphids completed their development one day later than the aphids reared on infected leaves of this cultivar and those which matured on healthy or infected leaves of cv. Diana. Mean weight of apterous virginoparae, mean relative growth rate, and intrinsic rate of natural increase were enhanced if the aphids were reared on infected leaves of either cultivar. Mean total progeny per female increased only on infected leaves of cv. Bolero, but not on cv. Diana. 相似文献
17.
Upali Jayasinghe Jeanne Dijkstra 《European journal of plant pathology / European Foundation for Plant Pathology》1979,85(2):47-65
Two viruses were found in mosaic-diseased plants ofEucharis grandiflora in a glasshouse of the laboratory. One virus with a normal particle length of 733 nm caused local lesions onHyoscyamus niger and mosaic symptoms in leaves of healthy-lookingEucharis andHippeastrum plants. On the basis of its host range, physical properties and serology it was identified asHippeastrum mosaic virus, a member of the potyvirus group. This was confirmed by the presence of spherical nuclear inclusions and pinwheels in different tissues of diseasedEucharis plants. The second virus with a normal particle length of 598 nm was present in both healthy-looking and mosaic-diseasedEucharis plants, and it inconsistently induced local lesions onGomphrena globosa. According to its morphology and its reaction onGomphrena, it might be identical or related toHippeastrum latent virus. Crystal-like inclusions were observed in the cytoplasm of cells of both healthy-looking and mosaic-showingEucharis leaves. As no virus-free seedlings ofEucharis were available, the virus nature of these inclusions could not be established. 相似文献
18.
D. Chandler 《Phytoparasitica》1992,20(1):S11
The lettuce root aphid,Pemphigus bursarius, is a commercially important pest of lettuce and occupies a niche amenable to the action of entomopathogenic fungi. As the first stage of a biological control programme, a bioassay was developed against adult apterousP. bursarius. An isolate ofMetarhizium flavoviride was pathogenic toP. bursarius and sporulated abundantly upon aphid cadavers. However, two isolates ofVerticillium lecanii, pathogenic against glasshouse whitefly and aphids, were only weakly pathogenic toP. bursarius. 相似文献
19.
J. J. de Wijs 《European journal of plant pathology / European Foundation for Plant Pathology》1975,81(4):144-148
A field survey and testing of leaf samples have given an impression of the distribution of passionfruit ringspot virus in twoAdenia and twoPassiflora spp. in Ivory Coast. The data suggest thatAdenia spp. are the original host plants of the virus. Introduction to Ivory Coast of the virus withP. edulis seems unlikely. Since theAdenia spp. prefer forest and shrub vegetations and aphid flights are shorter in the dryer savannah areas of the North, the cultivatedP. edulis has chances to remain healthy over a prolonged period of growth, which is excluded in the South of the country. 相似文献
20.
A new boll rot disease of cotton (Gossypium hirsutum L.) cv. MCU 9 was observed in Tamil Nadu, India, in 1988. The causal organism was isolated in pure culture and identified asCorynespora cassiicola (Berk. & Curt.) Wei. The isolate, which on cotton is pathogenic only to bolls, is considered to be different from a strain ofC. Cassiicola known elsewhere causing leaf spot of cotton. The pathogenicity of this fungus on several other important crops was also tested. The fungus produced leaf spot and stem rot diseases on, respectively, eight and six host plants. Root rot, after inoculation, was observed only inVigna sinensis, Arachis hypogaea andSesamum indicium. 相似文献