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EFFECTS OF ACUTE SIMULATED AND ACUTE GRASSHOPPER (ORTHOPTERA: ACRIDIDAE) DAMAGE ON GROWTH RATES AND YIELD OF SPRING WHEAT (TRITICUM AESTIVUM)1

Published online by Cambridge University Press:  31 May 2012

O. O. Olfert
Affiliation:
Research Station, Agriculture Canada, Saskatoon, Saskatchewan S7N 0X2
M. K. Mukerji
Affiliation:
Research Station, Agriculture Canada, Saskatoon, Saskatchewan S7N 0X2

Abstract

Studies showed that the type of damage, the timing of damage with the phenological stage of the crop, and the amount of available soil moisture influenced the growth response of spring wheat to acute levels of grasshopper damage and acute levels of artificial damage. Ground-level cutting of plants resulted in the greatest reduction in plant biomass and crop yield, while grasshopper damage and artificial stripping of leaf material did not result in as severe a reduction in either biomass or yield.

Damaged plants were not able to recover lost biomass when damage occurred any later than the early stages of tillering despite observed relative growth rates which were higher than control plants. The greatest degree of recovery occurred in study sites with the greatest amount of available soil moisture.

The most detrimental effect of damage on yield was the reduction of heads per plant and kernel weight. In most cases differences in the number of seeds per head between damaged and control plants were not evident.

Résumé

L'étude conclut que les facteurs qui influent sur la croissance des peuplements de blé de printemps infestés par les sauterelles ou endommagés par un moyen artificiel sont : (1) le type de dégât, (2) le stade phénologique du peuplement et (3) la teneur en eau du sol. La coupe au ras du sol provoque la plus importante baisse de biomasse et de rendement, les dégâts causés par les sauterelles et la défoliation artificielle ayant des effets moins prononcés.

Seules les plantes endommagées aux tout premiers stades du tallage ont pu réprendre la biomasse perdue, bien que toutes les plantes avariées aient présenté un taux de croissance plus élevé que les plantes témoins. La teneur en eau du sol favorisa la récupération de la biomasse perdue.

Le pire effet des dégâts sur le rendement se traduit par une baisse du nombre d'épis par plante ainsi que du poids du grain. Dans la plupart des cas, il n'y a pas de différence entre le nombre de grains par épi chez les plantes avariées et chez les plantes témoins.

Type
Articles
Copyright
Copyright © Entomological Society of Canada 1983

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