Crop losses: The need to quantify the effects of pests, diseases and weeds on agricultural production

Walker, P. T.

doi:10.1016/0167-8809(83)90038-5

Cited by 49 publications

(24 citation statements)

References 87 publications

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“…Although crop damage may not always result in yield loss, Nwanze (1988), and Leuschner et al (1985) stressed that in all yield loss studies conducted at ICRISAT, deadhearts are one of the most important factors. Yield loss assessment methods have been discussed by several authors (Chiarappa, 1981;Teng, 1987;Walker, 1981Walker, , 1983Nwanze, 1988;Seshu Reddy, 1988;Seshu Reddy and Walker, 1990;Youm, 1990). Yield loss due to insect pests can be expressed as 'avoidable' and 'indirect' losses.…”

Section: P Earl Millet Pennisetum Glaucum (L) Rmentioning

confidence: 99%

“…Yield loss due to insect pests can be expressed as 'avoidable' and 'indirect' losses. Avoidable loss is best expressed as the reduction in the maximum, potential or attainable yield in the absence of the causal pest, expressed as a percentage of that attainable yield (Walker, 1983). Indirect losses are due to deadhearts and non-harvestable heads (NRI, 1993).…”

Section: P Earl Millet Pennisetum Glaucum (L) Rmentioning

confidence: 99%

“…Stems with harvestable heads were cut and brought to the laboratory where they were placed individually in labelled bags and sun-dried for about 10 days. Yield was evaluated by weighing threshed grains to the nearest 0.01 g. Percent avoidable loss in yield (w %) was calculated using the formula reported by Walker (1983): w% = (my)/m x 100, where m = yield obtained in control plots and y = yield obtained in a particular treatment.…”

Section: Artificial Infestationmentioning

confidence: 99%

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Assessment of Grain Yield Losses in Pearl Millet Due to the Millet Stemborer, Coniesta ignefusalis (Hampson)

Drame-Yaye

Youm

Ayertey

2003

Int. J. Trop. Insect Sci.

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Abstract-Studies were conducted at the ICRISAT Sahelian Centre, Niger, to assess damage and yield loss by the millet stemborer, Coniesta ignefusalis (Lepidoptera: Pyralidae) on Pennisetum glaucum (L.) R. Brown. Although 78% of stems were infested, late attack by the millet stemborer on millet plants resulted in bored stems yielding more than unbored ones. Artificial infestations with 5 and 10 larvae per plant at 2 weeks after plant emergence (WAE) resulted in 50 to 70% plants with deadhearts and 24 to 100% avoidable yield loss. At 4 weeks after plant emergence, infestations with 5 larvae and 10 larvae per plant resulted in 7% increase in yield and 16% yield loss, respectively. Therefore, both the age of plant and density of borer population at the time of infestation can influence resulting stemborer damage and yield loss on pearl millet.

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Section: P Earl Millet Pennisetum Glaucum (L) Rmentioning

confidence: 99%

Section: P Earl Millet Pennisetum Glaucum (L) Rmentioning

confidence: 99%

Section: Artificial Infestationmentioning

confidence: 99%

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Assessment of Grain Yield Losses in Pearl Millet Due to the Millet Stemborer, Coniesta ignefusalis (Hampson)

Drame-Yaye

Youm

Ayertey

2003

Int. J. Trop. Insect Sci.

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“…These are used to calculate the probability that a randomly chosen field will suffer a percentage yield loss greater than a specified level. be prevented by a nonphytotoxic herbicide (Walker 1983). Thirdly, if all herbicides were less than 100% effective, the preventable yield loss percentage would be underestimated.…”

Section: Product Minimum Treatment Breakeven Herbicide Product (Activmentioning

confidence: 99%

“…Yield losses caused by weeds in cereal crops have not been satisfactorily quantified in New Zealand and so the parameters of even simple models relating yield loss to weed density (Cousens 1985) cannot be estimated. Consequently the costlbenefit analyses necessary for rational decision-making in weed control (Walker 1983) cannot be carried out for New Zealand crops.…”

Section: Introductionmentioning

confidence: 99%

The economics of herbicide use in cereal crops in New Zealand

Bourdôt¹,

Saville²

1988

New Zealand Journal of Experimental Agriculture

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A simple model of net return for herbicide usage in cereals, based on yield losses caused by weeds, was used to derive breakeven losses for herbicides used in New Zealand. For wheat crops with average yields (4.5 t/ha) at 1987 prices, breakeven losses varied from 2.1 % to 9.2% for weeds other than wild oats (Avenajatua), and from 6.4% to 14.1 % for wild oats. For barley crops with average yields (4.5 t/ha), breakeven losses varied from 3.0% to 13.1 % for weeds other than wild oats, and from 9.1 % to 20.2% for wild oats.A comprehensive survey of yield losses attributable to weeds in cereal crops has not been undertaken in New Zealand. However, using data available from Canada, breakeven yield losses would usually be exceeded for most of the 28 herbicides used in New Zealand cereal crops. On this basis there is no economic justification for the current trend toward reduced herbicide use in cereals.

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Injury and Yield Losses Due to the Maize Stem Borer Busseola fusca (Fuller) (Lepidoptera: Noctuidae) on Smallholder Farms

Ndjomatchoua

Tonnang

Tchawoua

et al. 2020

Sustainable Management of Invasive Pests in Africa

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Crop losses: The need to quantify the effects of pests, diseases and weeds on agricultural production

Cited by 49 publications

References 87 publications

Assessment of Grain Yield Losses in Pearl Millet Due to the Millet Stemborer, Coniesta ignefusalis (Hampson)

Assessment of Grain Yield Losses in Pearl Millet Due to the Millet Stemborer, Coniesta ignefusalis (Hampson)

The economics of herbicide use in cereal crops in New Zealand

Injury and Yield Losses Due to the Maize Stem Borer Busseola fusca (Fuller) (Lepidoptera: Noctuidae) on Smallholder Farms

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