摘要:

SummaryThe effect of temperature, photoperiod, artificial diet and water on the termination of diapause by larvae of the stem borer,Chilo partellus(Lepidoptera: Pyralidae), was studied in the laboratory. Termination of diapause as indicated by pupation was affected mainly by a combination of high temperature and a long day photoperiod. Total darkness did not prevent termination of diapause and pupation occurred also in larvae which were never exposed to water. Long days accelerated pupation, but, under 16 h daylength, termination of diapause was faster than under constant illumination. Provision of artificial diet had no effect or slowed down pupation but water decreased the time to pupation. Under 28°C, 16 h daylength and availability of water,C. partellusdiapausing larvae terminated diapause and pupated in about 9 days

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1993.tb04065.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryStrains of the aphidAphis gossypii,taken from cucumber in UK glasshouses were tested for resistance to pirimicarb, diazinon and heptenophos. Compared to a susceptible strain, resistance factors to diazinon of up to 659 were found in populations collected between 1987 and 1989. Compared to the same susceptible strain, diazinon‐resistant populations also showed a reduced response to heptenophos. All field populations tested against pirimicarb were resistant. Host plant preference tests showed that all strains (including stock cultures) tested could readily breed on cotton. However strains originally collected from chrysanthemum did not transfer to cucumber and likewise strains from cucumber would not colonise chrysanthemum. Polyacrylamide gel electrophoresis of four of the aphid strains showed differences in migration rates and intensity of staining of esterase bands. Intensity of staining was correlated with the degree of diazinon resistanc

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1993.tb04066.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryTwelve varieties of cowpea(Vigna unguiculata)were tested at the seedling and podding growth phases for resistance to infestation and damage toAphis craccivoraKoch. Nine of these cowpeas have previously been known to exhibit seedling resistance and the other three, susceptibility to the insect.A. craccivoracould not colonise pods of TVu 9930. Pods of Tvu 36 also manifested a high level of resistance to the aphid. The three seedling susceptible varieties proved quite susceptibleto A. craccivoraat the podding phase. The other varieties were more resistant to the aphid in the seedling phase than in the podding phase.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1993.tb04067.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryShoot tip culture was used to eliminate white clover mosaic virus (WCMV) and red clover necrotic mosaic virus (RCNMV) from red clover, and clover phyllody disease (CP) and clover red leaf disease (CRL) from white clover. Shoot tips up to 2.4 mm (in some cases 3 mm) could regenerate plants free from the pathogens, but the efficiency of elimination, at least for WCMV and CRL, tended to decrease with increasing shoot tip size. The efficiency of plant regeneration from shoot tips generally improved with increasing tip size.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1993.tb04068.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryThis is the first record of seed transmission of turnip yellow mosaic virus (TYMV) in oilseed and turnip rapes. The seed transmission of TYMV in a naturally infected winter turnip rape(Brassica napusvar.silvestris)cultivar Perko PVH was investigated. By ELISA 1.6%, 3.2% and 8.3% seed transmission of the virus was found in seed of plants from three localities.The proportion of infected seeds produced by artificially infected plants of winter oilseed rape(Brassica napusssp.oleifera)and winter turnip rape cultivars was determined. The virus transmission rate, expressed as the proportion of virus‐infected plants which germinated from the seed was for the oilseed rape cvs Jet Neuf 0.1%, Solida 0.4%, Silesia 0.8%, Darmor 1.2%, SL‐507 0.2%, SL‐509 0.0% and for the winter turnip rape cv. Perko 1.5%. ELISA cannot be used in direct tests on bulk seed lots to estimate proportion of infected seed, but must be used on germinated seed

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1993.tb04069.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryThe effects of growing one, two or three years of resistant barley or winter wheat on barley mild mosaic virus were studied in experiments on two naturally‐infested sites in Gloucestershire and Cambridgeshire. Disease incidence and yield of the susceptible cultivars Igri and Maris Otter following a three year break were not significantly different from those of control plots that had grown continuous susceptible barley. The effects of cropping sequence treatment on soil populations of the fungus vector,Polymyxa graminis,were assessed by estimating most probable numbers of propagules following bioassays. Variability was large and neither total numbers of propagules, nor those carrying virus, was significantly affected by the cropping treatment

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1993.tb04070.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryThe detectability of hop latent viroid (HLVd) was investigated in field‐grown hop(Humulus lupulusL.; an herbaceous perennial in which all the aerial parts die at the onset of winter) plants, using dot‐blot hybridisation. The viroid was readily detected in all aerial tissues in the second half of the growing season but it could not be detected very early in the season. Between early‐ and mid‐season, HLVd was first detected at the base of the new stems and then apparently spread up them as they grew but only became detectable near the tips of the shoots at mid‐season, approximately at the time most elongation growth ended and flowering began. Petioles were the most convenient tissues to test, being easy to collect and, relative to leaf lamina tissue, low in inhibitors. Both dot‐blot andin situhybridisation failed to detect HLVd in shoot tips taken from plants grown at two ‘low’ temperatures (10°C and 15°C). Failure to produce any viroid‐free plants byin vitroculture from such tips suggested that they did contain viroid but at levels too low to detect by either method. Lower temperatures and smaller explants are now being investigated as means of producing

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1993.tb04071.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryA soil‐borne mosaic disease of winter wheat in Sichuan, Shaanxi, Hubei and Henan provinces was associated with infection by a virus with filamentous particles and that in Shandong, Anhui, Jiangsu and Zhejiang provinces by co‐infection with this virus and soil‐borne wheat mosaic virus. The virus with filamentous particles was identified serologically, by particle sizes, cytopathology and the molecular weights of the coat protein and the two RNA species to be either wheat spindle streak mosaic virus (WSSMV) or wheat yellow mosaic virus. These viruses are probably isolates of the same virus and the name WSSMV is preferred. In baiting tests using infested soil, the dilution endpoints for detecting WSSMV were 1/625‐1/15625, and for the fungus vector,Polymyxa graminis,1/3125

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1993.tb04072.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryEnzyme‐linked immunosorbent assay (ELISA)‐based surveys of the occurrence of five barley yellow dwarf virus (BYDV) serotypes (MAV, PAV and SGV in “Group 1”; RPV and RMV in “Group 2”) in CIMMYT bread wheat nurseries and other small grain crops in various locations world‐wide were undertaken in 1988, 1989 and 1990. The objective was to investigate the relative occurrence of BYDV serotypes in areas relevant to CIMMYT cereal breeding programs. Overall, MAV and PAV serotypes predominated in the samples collected, though their relative frequencies depended on the location. SGV serotypes were uncommon in most locations. Group 2 serotypes occurred widely, but RMV serotypes were more common than

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1993.tb04073.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryHeterodera cajaniis an important nematode pest of pigeonpea in India. Evaluation of 58 pigeonpea cultivars and 61 accessions ofCajanus acutifolius, C. cajanifolius, C. grandifolius, C. lanceolatus, C. lineatus, C. mollis, C. pla‐tycarpus, C. reticulatus, C. scarabaeoides, C. sericeus, C. volubilis, Flemingia macrophylla, F. stricta, F. strobilifera, Rhynchosia aurea, R. bracteata, R. cana, R. densiflora, R. minima, R. rothii, R. suaveolensandR. sublobatarevealed that the tested pigeonpea cultivars lacked resistance toH. cajani.Eight accessions of wild relatives were resistant and 20 accessions were moderately resistant. Based on the white cyst number on roots and low plant‐to‐plant variation, two accessions ofC. scarabaeoides(ICPWs 111 and 128), three accessions ofFlemingiaspp. (ICPWs 194, 202 and 203), and one accession each ofR. rothii(ICPW 257),R. densiflora(ICPW 224), andR. aurea(ICPW 210) were identified as resistant and promising for use in intergeneric hybridisation progr

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1993.tb04074.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY