摘要:

Insect pests and their damage were observed in a new early‐maturing maize variety and a common traditional variety, cultivated with and without chemical fertilizer in highland Ecuador. Observations were made on unsprayed experimental plots from farmers’ fields: at early whorl (25–29 days after planting), mid‐whorl (69–80 days), and during ear maturation (148–203 days after planting). Foliar damage by the principal pestsAgrotis deprivataandDargida grammivoralarva was minimal. The early‐maturing variety suffered significantly more earworm damage from Ecuador's three principal pests of ripening maize:Heliothis zea, A. deprivataandEuxesta eluta.Of the traditional and early varieties respectively, 24.4% and 35.6% of the ears were damaged by Lepidoptera larvae, and 19.5% and 24.2% byE. eluta.The greater damage observed in the early variety may be the result of reduced husk tightness. Two parasites were reared fromA. deprivatalarvae collected in maize whorls,Thymebatissp., Fam. Ichneumonidae andArchytas marmoratusFam. Tachinidae. There was no significant yield difference between the two varieties. However, the new variety's greater susceptibility to insect damage may reduce its adoption by the small‐scale farmers for whom it was developed, and its use may initiate pesticide applications where not previously used.

ISSN:0143-6147    

DOI:10.1080/09670879109371626

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

During recent years, blister beetles have gained importance in species diversity and as pests of food crops in West Africa. Among the 97 species reported,Psalydolytta fuscaOliv, andP. vestitaDuf. are economically important beetle species. Beetle abundance is generally associated with the flowering of crops in a region. Regular intensive weeding and early crop establishment are recommended for pest management in food crops. Global pest control strategies are discussed in the context of subsistence agriculture.

ISSN:0143-6147    

DOI:10.1080/09670879109371627

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Cucurbits are important crops for both staple and dessert foods. Past reviews have not covered insect resistance in cucurbits thoroughly, especially since much work has been done recently. Screening methods make a large difference in the efficiency of selection for resistance to insects. Resistance of cultigens should be evaluated using several biotypes of each insect being evaluated, and efficient test conditions with good control of environment. If possible, laboratory tests should be used to improve the repeatability and to reduce experimental error. Resistance to insects has been identified in cucurbits. For example, muskmelons have been identified that have resistance to melon aphid and red pumpkin beetle. On the other hand, resistance to pickleworm has not been identified after screening hundreds of cucumber cultigens. Conclusions drawn on the role of cucurbitacins in insect resistance to cucurbits are not unanimous. Studies on the genetic control of resistance in cucurbits indicate that there are at least 13 crop‐insect cases where there is heritable resistance. With greater emphasis in cucurbit breeding programmes, multiple insect resistance should be obtainable in many of the cucurbit species.

ISSN:0143-6147    

DOI:10.1080/09670879109371628

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

It is suggested that anatto(Bixa orellana)may be a suitable trap crop forHelopeltis schoutedeniReut. in tea and possibly other crops.

ISSN:0143-6147    

DOI:10.1080/09670879109371629

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Action thresholds for initiating insecticide sprays based on peak egg laying and flat pod damage were evaluated in the field for the pod borer,Adisura atkinsoniMoore on field (hyacinth) bean. An initial spray at peak egg laying and tender pod stage, followed by sprays to maintain 0.5 flat pods damaged/inflorescence reduced pod and seed damage and maximized the yield and net returns. In addition, the investigation resulted in fewer insecticide applications than calendar‐based sprays.

ISSN:0143-6147    

DOI:10.1080/09670879109371630

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Studies on the use of 22 chemical attractants forGlossina tachinoideswere undertaken in Côte d'Ivoire following earlier work onG. m. morsitansand G.pallidipesin Zimbabwe. While catches of G.m. morsitansand G. pallidipes increased by several times when traps were baited with some of these substances, catches ofG. tachinoideswere only marginally increased. G.tachinoidesis slightly attracted by octenol and acetone, alone or in combination, and its response to CO2is much weaker than that of the species tested in Zimbabwe. Phenol and indol mixtures both showed dose‐response relationships with catch. The indols were more potent in the lowest of the tested dosages (catch increase of 52%,P <0001) whereas the phenols showed better attractiveness in their higher concentrations (catch increase of 42%,P< 0.05). Odour is probably less important in host finding for the riverine species G.tachinoidesthan it is for the savanna species studied in Zimbabwe.

ISSN:0143-6147    

DOI:10.1080/09670879109371631

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0143-6147    

DOI:10.1080/09670879109371632

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0143-6147    

DOI:10.1080/09670879109371633

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0143-6147    

DOI:10.1080/09670879109371605

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor