摘要:

SUMMARYColonies ofMyzus persicaeandBrevicoryne brassicaewere established on artificial diets and the honeydew produced by them collected on aluminium foils. The diets were later exchanged for others containing a range of14C‐phorate concentrations. The honey‐dew produced while feeding on the treated diets was collected separately and mortalities were recorded. The diets, aphids and their honeydew were subsequently analysed.About 1.6% of the doses applied initially were found in the diets at the end of the bio‐assay period. Thin‐layer chromatography of diets containing LC50concentrations of insecticides showed that phorate and its metabolites were present in similar proportions. The LC50values were 15.5 nM and 277 nM phorate equivalents forB. brassicaeandM. persicaerespe

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1981.tb05135.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYFundatrices died when caged on senescent leaves of bird cherry on which oviparae thrived. Fundatrigeniae had more ovarioles and a higher reproductive rate than fundatrices. Oviparae developed and matured eggs on unfurling leaves but they took longer to reach maturity and grew more slowly than when reared on senescent leaves. Fundatrices and oviparae in addition to having an intrinsic preference for bird cherry over other plants did better on particular growth stages of their primary host.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1981.tb05136.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYA strain of the rust fungusPuccinia chondrillinaintroduced into Australia in 1971 for the biological control of skeleton weed,Chondrilla juncea, attacked only the narrow‐leaf form of this weed. Studies were, therefore, undertaken in the Mediterranean region to discover strains of the rust which will attack the other two Australian forms of skeleton weed, intermediate‐ and broad‐leaf. Several strains of the rust were found to be highly virulent against the intermediate form. One of these strains from Manisa, western Turkey, was both highly specific to its host and safe for use as a biological control agent. This strain has recently been introduced into Australia for the control of the intermediate form ofChond

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1981.tb05137.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYSevere epidemics of triticale leaf rust were controlled by a single treatment with 4‐n‐butyl‐1,2,4‐triazole (triazbutyl) as a foliar spray or as broadcast application on soil followed by irrigation. A single foliar spray of triazbutyl at 0.5 litre a.i./ha approached the control obtained by 1.0 litre a.i./ha. Effective control was obtained by spraying 10 days before or 10 days after the rust appearance but later spray applications were less ef

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1981.tb05138.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYSpiroplasma isolated from naturally diseased corn (Zea mays) plants in Jamaica, produced symptoms typical of the Rio Grande strain of corn stunt spiroplasma (CSS) following experimental transmission to corn byDalbulus maidis.Isolates were serologically closely related to a reference culture of CSS. Bacilliibrm virus‐like particles associated with a related disease condition were transmitted experimentally to a small proportion of plants byD. maidis.Both virus‐like particles and CSS were detected in one experimentally infected plant, suggesting that this leafhopper could acquire both agents and transmit then simultaneously to c

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1981.tb05139.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYTrials at three sites in north‐western Tasmania monitored the spread of subterranean clover red leaf virus into and within broad bean crops with movement of its vector,Aulacorthum solani.Records indicated that almost all infections within the crops resulted from secondary spread by apterae following the establishment by migrant alatae of a very few foci of infestation and infection soon after crop emergence. Spread of the virus within the crops was reduced by sprays of demeton‐S‐methyl. Incidence of infection in sprayed plots at harvest was 23%, 13% and 23% at the three sites compared with 80%, 31% and 84% respectively, in unsprayed plots. Yield increases as a result of spraying were 980, 420 and 540

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1981.tb05140.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYThe ability of 10 nematode species to transmit three strains of cherry leaf roll virus (CLRV) was tested by three methods: (1) virus‐infected source plants and virus‐free bait plants were grown concurrently in nematode‐infested soil, (2) as for (1) but virus source plants were removed before bait plants were planted, and (3) nematodes were extracted from soil after access to virus source plants, and were added to pots containing bait plants. The occurrence of galls on roots showed that nematodes fed both on source and on bait plants in all experiments and, in some experiments, CLRV was detected by direct assays (slash tests) ofLongidorus elongatus, L. leptocephalusandParalongidorus maximus.Although the nematodes readily transmitted control viruses, for which they are known to be vectors, CLRV was detected by root assays in only a few bait plants exposed toL. elongatus, L. macrosoma, Xiphinema diversicaudatumorL. leptocephalus + X. vuitteneziin tests by method 1. The recovery of CLRV in these tests is interpreted as being due to contamination.These results add to the increasing circumstantial evidence against the involvement of nematodes in the transmission of CLRV. Other possible mechanisms of spread are disc

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1981.tb05141.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYA strain of cassava latent geminivirus (CLV) was isolated from mosaic‐affected cassava plants from coastal districts of Kenya. This virus (CLV‐C) did not infectNicotiana clevelandii, a diagnostic host of the type strain (CLV‐T); experimental host range was very restricted and CLV‐C only infectedN. benthamianaandN. rusticaout of several solanaceous hosts readily infected by CLV‐T.CLV‐C was also isolated from naturally infectedJatropha multifida(Euphorbiaceae) andHewittia sublobata(Convolvulaceae).CLV‐C was propagated inN. benthamianawith difficulty and only those isolates derived from cassava plants infected with severe mosaic symptoms were maintained more or less successfully; these sources usually contained a higher concentration of CLV than plants with mild symptoms. Symptom variants generally remained unchanged when grafted into a highly susceptible South American cassava variety.CLV‐C and CLV‐T seemed to occur respectively only in coastal and western districts but their ranges overlapped in central Kenya where they could have been introduced in infected material.CLV‐C could be purified satisfactorily with the method used for CLV‐T but only after modifying the procedure by substituting phosphate for borate in the extraction buffer,n‐butanol forn‐butanol/chloroform in clarification of extracts, and phosphate for borate buffer when resuspending concentrated virus.A virus serologically indistinguishable from CLV‐T was isolated from mosaic‐ affected material obtained from Nigeria; East African and Nigerian isolates were essentially similar in host range and symptomatology. In gel‐diffusion serology tests, pronounced precipitation spurs developed between CLV‐T and CLV‐C indicating that the isolates were related but not identical serologically.Symptoms typical of cassava mosaic disease appeared in only three of 105 plants in experiments on transmission of CLV‐C and CLV‐T by whiteflies, when attempted acquisition of either clarified CLV‐infective sap or purified CLV was made through ‘Parafilm’ membranes. Because it is possible that the three infections resulted from contamination, they cannot constitute proof of transmission. The presence of CLV in relation to the etiol

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1981.tb05142.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYThe concentrations of cucumber mosaic (CMV) and alfalfa mosaic viruses, present in various types of cultured plant tissues, were significantly less when ribavirin (syn. Virazole) at 50 or 100 mg/litre was present in the culture medium. CMV concentrations decreased within 24 days in infected cultures treated with ribabirin, but incubation periods of up to 127 days were required before the virus was undetectable. However, virus‐free cultures were obtained from CMV‐infected meristem‐tips irrespective of the presence or absence of ribavirin. Kinetin at concentrations up to 25.6 mg/litre had no persistent antiviral e

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1981.tb05143.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYA nematode parasitic on prepupae of larch sawfly (Cephalcia lariciphila) appears to be indistinguishable fromNeoaplectana carpocapsae.Of three temperatures tested the optimum for development was 25 °C at which most eggs were produced in both the first and second generations. Infective nematodes entered sawfly prepupae through the anus and mouth, but the preferred mode of entry was through the spiracles; prepupal hosts were extremely attractive to infective nematodes. Nematodes overwintered in prepupal hosts and in the soil. Dauerlarvae penetrated 10 cm of packed moist soil to infect prepupae constrained at the bottom of a vertical tube, sawfly mortality decreasing with depth. Dauerlarvae may also migrate 8 cm horizontally, and 5 cm upwards, to invade the host.It is suggested that the nematode could be used to supplement biological control ofCephalcia lariciphila

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1981.tb05144.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY