摘要:

The amount of rat damage to immature coconuts was assessed by two methods. The first involved fortnightly recordings of all coconuts produced, including those rat damaged, at representative sites for up to three years. The second method attempted to utilise decay characteristics of rat damaged coconuts as a basis for projecting spot counts of damaged coconuts to long term estimates of damage.

ISSN:0030-7793    

DOI:10.1080/09670877409418213

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Trials to determine if the costs of eradicating G. morsitans by aerial application of endosulfan (Park et al 1972) might be reduced, were carried out using lower quantities of the pesticide. Area dose rates were varied by altering; the swath width, the insecticide output per unit flying time and the insecticide concentration. The trials were judged by the reduction of the adult tsetse population after a single application. Results indicated that eradication of G. m. morsitans under the conditions prevailing in N.W. Botswana, is possible by the repeated application, at 21 day intervals, of 20% endosulfan at 3.0 //km2(0.6 kg a.i./km2). Applications should be made at a swath interval of 274m, using a single AU 3000 Britten-Norman Micronair unit to produce spray droplets mostly smaller than 40μm diam. The cost (1973) of each application (aircraft and insecticide only) was approximately US $13.00/km2for an area in excess of 1000 km2.

ISSN:0030-7793    

DOI:10.1080/09670877409418214

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Granular applications of prophos 5 g a.i., phenamiphos 3 g a.i., carbofuran 2.5 g a.i. and oxamy! 6 g a.i. to bananas in the planting holes and subsequent surface applications at 2, 6, 10, 14 and 18 months after planting have given good nematode control as compared with a standard DBCP (dibromochloropropane) (75% e.c.) application of 11.23 l/ha (5.7 cc per plant) every six months and untreated plots. Although the differences in plant crop yields are not statistically significant the production cycle of the granular nematocide treatments was 23–30 days faster than that of control and DBCP treatments. Production data from the ratoon crop indicates a similar pattern.

ISSN:0030-7793    

DOI:10.1080/09670877409418215

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The use of one source of cytoplasmic male steriity, leading to widespread uniformity of maize, coupled with the appearance of a new virulent race of Helminthosporium maydis made the Southern Corn Leaf Blight epidemic possible. The weather during 1970 was very suitable for the spread of the disease and thus the epidemic occurred. The possible role of cytoplasmic DNA, carried most probably by the mitochondria, in the susceptibility or resistance of various maize lines in discussed. The relationship of cytoplasmic male sterility and disease resistance or susceptibility is considered. The effects of the pathotoxin, produced by H. maydis, its uses as an experimental tool in research, and its potential uses in further investigations are described in detail.

ISSN:0030-7793    

DOI:10.1080/09670877409418216

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The major pulse crops in India are gram, pigeon pea, black gram, green gram, lentil and peas. Gram, pigeon pea and pea are attacked by several diseases some of which cause considerable crop damage. Gram is affected mainly by wilt (Fusarium oxysporum f. sp.ciceri Matuo and Sato), blight (Mycosphaerella pinodes B. and Blox) and rust (Uromyces ciceris-arietinii (Grogn.) Jacz. & Boy.). The main diseases of pigeon pea are wilt (Fusarium oxysporum f. sp.udum (Butler) Snyd. and Hans.), and sterility mosaic. Powdery mildew (Erysiphe polygoni DC) and rust (Uromyces vicia-fabae (Pers.) Schroet.) are the most important pea diseases. Some diseases of minor importance are described. Details are given of the symptoms, distribution and control of the diseases with particular reference to those of economic importance. Several minor diseases of lentil, green gram and black gram are included.

ISSN:0030-7793    

DOI:10.1080/09670877409418217

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The two major fungal diseases of rice in Nigeria are rice blast (Pyricularia oryzae Cav.) and brown spot (Cochliobolus miyabeanus (Ito and Kuribayashi) Dreschler ex Dastur). The loss in grain yield attributable to these diseases ranges from 11.5–39.6% and 12–43% respectively, Mancozeb, blasticidin-S, fentin hydroxide, benomyl and edifenphos as foliar sprays effectively control rice blast in the laboratory and field. Brown spot is controlled by spraying with thiram, mancozeb or blasticidin-S. A more useful approach to the control of these diseases being adopted in Nigeria is the search for horizontally resistant varieties. Other fungal diseases of rice in Nigeria are the green smut (Ustilaginoidea virens (Cooke) Tak.), basal sheath rot (Rhizoctonia solani Kühn), sheath blight (Corticium sasakii (Shirai), Matsumoto.), leaf scald (Rhynchosporium oryzae Hashioka and Yokogi), narrow brown leaf spot (Cercospora oryzae Miyake) and bakanae disease, a foot rot caused by Fusarium moniliforme Sheldon. Two suspected cases of virus diseases have been reported; grassy stunt disease (transmitted by Nilaparvata lugens Stal.), and orange leaf disease (transmitted by Inazuma dorsalis (Motschulsky). No bacterial disease of rice has been found in Nigeria.

ISSN:0030-7793    

DOI:10.1080/09670877409418218

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Seven new granular herbicides were evaluated in Taiwan for the control of weeds in broadcast flooded rice. In general, herbicides applied early (6 days after seeding) gave better weed control but caused more crop damage than when applied late (12 days after seeding). Benthiocarb applied at 6 days after seeding, when most weeds were at the one to two leaf stage, was highly selective in controlling broad-leaved weeds and sedges with no sustained injury to rice. Butachlor failed to control broad-leaved weeds at the two to three leaf stage. The initial toxicities of C-288 (dimethatryn plus piperophos, 1:4) piperophos (C-19490), and CRD 71.6388 were too severe to warrant their use in direct-seeded flooded rice in Taiwan. Among the herbicides tested, thiochlormethyl and molinate and thiochlormethyl when applied late, were the most selective. When applied 12 days after seeding or at the three to four leaf stage of weeds, both treatments provided excellent control of weeds without causing any crop injury.

ISSN:0030-7793    

DOI:10.1080/09670877409418219

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Twelve herbicides were screened for crop safety in up to 18 crops. Several of these herbicides were then tested in field trials in those crops in which they appeared promising. The results of field trials in maize, hot peppers, ginger and groundnuts are reported in detail.

ISSN:0030-7793    

DOI:10.1080/09670877409418220

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Among various organisms attacking skeleton weed,Chondrilla juncea, in Europe, a rust fungus,Puccinia chondrillina, and two powdery mildews,Erysiphe cichoracearumandLeveillula tauricaf. sp.chondrillaewere found to be the most damaging.P. chondrillinawas shown to be specific toChondrillaand has recently been introduced into Australia where skeleton weed is important in wheat cultivation. It has already spread throughout the weed infestations and is beginning to reduce plant populations. Encouraged by the result of theChondrillarust, the possible use ofPuccinia xanthiifor the control ofXanthium strumariumandX. spinosumhas also been studied. Current research on the possible use of phytopathogens in the biological control of some other weeds is reviewed.

ISSN:0030-7793    

DOI:10.1080/09670877409418221

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The Agricultural Research Service of the USDA has been actively engaged in research on the biological control of aquatic weeds since 1959. Research emphasis until 1967 was on alligatorweed,Alternanthera philoxeroides(Mart.) Griseb. As a result of this research, three species of insects from Argentina were released in the southeastern United States. Alligatorweed control with these natural enemies has been variable; but indications are that control will be substantial over most of the range of the weed.

ISSN:0030-7793    

DOI:10.1080/09670877409418222

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor