摘要:

SummarySurface sterilised stelar tissues from onion roots exhibiting typical pink root symptoms were plated on water agar and incubated under cool white fluorescent light (CWFL) for 12 h day‐1at 20°C. After 4–5 days, the plates were examined with the 10† objective of a compound microscope and tissues producing conidia ofFusariumspp. were discarded. Sub‐cultures of isolates suspected to bePyrenochaeta terrestris, grown fromFusarium‐negativetissues, were transferred to chloroamphenicol‐amended (500 ppm) corn‐meal (CCMA) agar plates and incubated at 24°C under CWFL for a further 10–14 days. Cultures with setose pycnidia were identified asP. terrestris. Plates were again scanned for conidia ofFusariumspp., and cultures negative forFusariumspp., but not producing pycnidia, were suspected to beP. terrestris. These were compared with known isolates on CCMA. On this medium growth ofP. terrestriswas slow, producing appressed, pinkish colonies which were circular with a smooth margin. All isolates ofP. terrestrisisolated by the procedure caused pink root of onion when tested, whereas none of theFusariumspp. isolated produced the disease. However, a mixed inoculums ofP. terrestrisandFusariurn solaniproduced typical p

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1989.tb06801.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryLaboratory experiments were carried out to evaluate the efficiency of two insecticides, cypermethrin and oxydemeton‐methyl, in controlling the nymphs and adults ofLygusbugs and the resulting damage caused by these bugs to small pine seedlings. Both insecticides significantly increased the mortality of bugs on the seedlings compared with bug mortality on untreated controls. Mortality of bugs was higher in the oxydemeton‐methyl treatment than in the cypermethrin treatment. The occurrence of seedlings with multiple leaders and the number of leader shoots per seedling were significantly decreased in insecticide‐treated seedlings. Mean number of leader shoots was significantly higher in seedlings treated with oxydemeton‐methyl than in seedlings treated with cypermethrin after a 24‐h exposure to nymphal instars ofLygus. The mortality of the pine seedlings was very low but significantly decreased in insecticidal treatments. Factors affecting the effects of different insecticides on bug mortality and their efficiency in controlling the multiple‐leadering phenomenon ar

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1989.tb06802.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryFollowing exposures to potato root diftusate of between 6 and 12 h, desiccation killed a proportion of juveniles in eggs ofG. pallidaand affected the hatching behaviour of survivors. In hatching tests of 9 wk duration, more juveniles hatched in the final wk from cysts, which were soahed and dried alternately for 9 wk than from cysts soaked in tap water for the final 2 wk only. Mustard root diffusate prevented eggs previously stimulated by potato root diffusate from hatching, but it did not alleviate the effects of desiccation.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1989.tb06803.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY