摘要:

Seven date palm varieties were screened against leaf spot under field conditions at Haryana Agricultural University, Hisar. Results over 3 yr observations revealed that variety Khadrawi was resistant, contracting disease intensity less than 5%, four varieties,viz.Hallawi, Hayani, Shamran and Zaidi were found susceptible whereas Barhee and Medjool were highly susceptible to leaf spot. Eight fungicides were evaluated for their efficacy against leaf spot under field conditions. Data from 2 yr experiments revealed carben‐dazim at the rate of 0.2% to be most effective followed by thiophanate methyl, while captafol was less effective.

ISSN:0143-6147    

DOI:10.1080/09670878909371336

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A survey on the entomopathogens ofHeteropsylla cubanain Baybay and Villaba, Leyte was conducted from May 1986 to June 1987. Among the entomogenous fungi collectedEntomoph‐thorasp. andFusariumsp. were the most prevalent, followed byPaecilomyces farinosusandHirsutella citriformis.Although epizootics often occurred in ViSCA, these were never observed in Villaba. Possible factors influencing the incidence of psyllid diseases in the two areas are discussed.

ISSN:0143-6147    

DOI:10.1080/09670878909371337

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Peanut stripe virus was detected in soybean in all of the major production areas of Taiwan, where it seems to occur at least as frequently as soybean mosaic virus. Several lines of the AVRDC soybean germplasm collection and of locally grown soybean cultivars were immune to this virus. Significant yield reductions of up to 90% occurred in susceptible cultivars. The 100‐seed weight was reduced by up to 50%. Seeds of plants artificially inoculated with the virus up to the R1 stage were abnormally discoloured. A low percentage of seed transmission (2%) was observed only in seeds collected from one of three cultivars ofGlycine max(KS‐8) which had been inoculated at the earliest (V‐1) stage of growth.

ISSN:0143-6147    

DOI:10.1080/09670878909371338

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The influence of isoproturon (1.0 kg/ha), metoxuron (1.6 kg/ha) and methabenzthiazuron (1.4 kg/ha) mixed with 2,4‐D (0.50 kg/ha) each at their 50% less dose and with surfactant (0.1 %) at their 25% less dose demonstrated that per cent control of wild oat and wild canary grass reduced when these herbicides were combined with 2,4‐D. Addition of surfactant improved the control of wild oat, wild pea, yellow sweet clover and commonvetch. Combination of urea herbicides and 2,4‐D increased the control of broad leaf weeds over urea herbicides applied alone. However, the control of broad leaf weeds was almost similar to 2,4‐D applied alone. Pre‐emergence application of urea herbicides was less effective than their post‐emergence applications. Reduced rate of isoproturon and metoxuron in combination with surfactant gave similar grain yield to that obtained at recommended doses of these herbicides applied alone.

ISSN:0143-6147    

DOI:10.1080/09670878909371339

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Two intercropping trials were established in 1985–1986 to compare the effects of inter‐row intercropping, intra‐row intercropping, and sole cropping of sorghum and groundnuts on emergency ofStrigashoots on sorghum. Intra‐row intercropping reduced density ofStrigasignificantly when compared with sole cropping of sorghum. This effect appeared to be soil temperature‐mediated. Soil temperatures in intra‐row intercropping were 2 °C lower and closer to the minimum threshold of 30 °C than in sole sorghum during the peak period of germination.

ISSN:0143-6147    

DOI:10.1080/09670878909371340

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Chemical weed control method was compared with the traditional hoe‐weeding practice in sorghum production. Traditional hoe‐weeding method showed slightly greater returns per hectare than the chemical weed control method. However, when returns to labour were considered, herbicide technology was superior to hoe‐weeding. Labour required for weeding was reduced by 60% with the use of herbicide. The technology thus reduced substantially, farmers’ dependence on hired labour for weeding operation. Traditional hoe‐weeding was found to be economically efficient given the current wage rate. The result therefore showed herbicide use as a useful complementary weedcontrolmeasure to hoe‐weeding on small farm holdings rather than a substitute in sorghum production.

ISSN:0143-6147    

DOI:10.1080/09670878909371341

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Pests were surveyed in farmers’ fields in Burkina Faso, Niger and northern Nigeria from 1980 to 1983, and field trials at research stations in Burkina Faso (1980 and 1981) and at the ICRISAT Sahelian Center in Niger (1984 and 1985).Acigona ignefusalisis widely distributed in West Africa but its predominance as the major stem borer of millet varies with location. There are two generations of the pest annually, with peaks in moth population in July and September. Diapausing larval population declines during the dry season from November to May. A progressive decline in borer infestation was recorded between 1983 and 1985 in Niger. Damage to early‐sown millet was usually low while late sowing resulted in severe stem tunnelling and unproductive tillers. However, under low levels of borer infestation an unprotected crop gave higher grain yield than one which was protected with insecticide.

ISSN:0143-6147    

DOI:10.1080/09670878909371342

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The relationship between sowing date and the maize stalk borer,Busseola fusca(Fuller) in terms of infestation rate, and crop damage was studied using ten successive sowing dates between April and July in 1985 and 1986. Different degrees of infestation byB. fuscawere recorded from all sowing dates. Early sowing in April and the early part of May had significantly lower infestations of first generation larvae. Levels of infestation by second generation larvae were significantly higher on late sowing dates. High infestation by second generation larvae appeared to be connected with the high biotic potential of the moths of the first, non‐diapause generation. Second generation larvae caused crop loss ranging from 22–5 to 100% while it was only 0–22.6% due to the first generation. In conclusion, delay of sowing later than April may result in serious crop yield loss due to the second generation larvae ofB. fuscain Awassa.

ISSN:0143-6147    

DOI:10.1080/09670878909371343

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Small‐scale farmers in northern Ecuador, at an elevation of 2500 m, place leaves of castor beans (Ricinus communis) in germinating corn fields to reduce two Coleoptera pest species (Pseudothinobatis rufinasus(Kirsch), Tenebrionidae, and an unknown genus, subfamily Naupactini, Curculionidae). The objective of this study was to determine howP. rufinasusis affected by castor leaves. In a preference study under laboratory conditions,P. rufinasuspreferred castor leaves to leaves of corn, cabbage or paper, yet they did not appear to consume the castor. Approximately 80% of the beetles associated with castor. leaves for 12 h or more exhibited paralysis. In the laboratory, castor leaves were not directly lethal toP. rufinasus.Similar levels of mortality occurred when beetles were kept in vials with the test materials for 10 days. In the field, castor leaves were placed between rows of recently planted corn, as local farmers do. Mortality ofP. rufinasuscollected from exposed leaves was compared toP. rufinasusmortality from similar leaves protected from the sun by small shelters. The development of paralysis prevented beetles from leaving the castor leaves to hide during the day and the resulting exposure to direct solar radiation significantly increased their mortalaity.

ISSN:0143-6147    

DOI:10.1080/09670878909371344

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Fifty‐seven varieties of fodder mustard (Brassicaspecies) were screened for aphid (Lipaphis erysimiKalt.) resistance during 1981–1985 under natural infestation at Jhansi, India. The variety, IM‐76–103 was found to be highly aphid resistant and high yielding but late maturing. A hybridization programme to remove late maturity is suggested.

ISSN:0143-6147    

DOI:10.1080/09670878909371345

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor