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The effect of plant density on populations of the cabbage root fly on four cruciferous crops
Author(s) -
FINCH S.,
SKINNER G.,
FREEMAN G. H.
Publication year - 1976
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1976.tb00597.x
Subject(s) - biology , overwintering , agronomy , plant density , population density , cultivar , horticulture , pupa , pest analysis , population , botany , larva , sowing , demography , sociology
SUMMARY To study the effects of plant density on populations of the cabbage root fly (Erioischia brassicae) , cabbage, cauliflower, Brussels sprout and swede were each planted in plots with twenty‐four concentric circles of plants at spacings ranging from 10 to 90 cm between the individual plants. Plants treated with a root drench of chlorfenvinphos and untreated plants were each sampled at ten plant densities which ranged from 1–5 to 68‐3 plants/m 2 . In the absence of insecticide, the numbers of overwintering cabbage root fly pupae produced ranged from c. four per m 2 at the lowest plant density to 200 per m 2 at the highest. The number of pupae per m 2 was proportional to plant density to the powers 0–98,0‐77,0–69 and o‐6i for the swede, cauliflower, cabbage and Brussels sprout crops, respectively. The magnitude of each cabbage root fly population was determined mainly by plant density but also by the cultivar used as host plant. The results suggested that, in a given locality, when changing from low to high plant density crops during a growing season it should be unnecessary to apply insecticide to control cabbage root fly; conversely, a change from high to low plant densities would necessitate an extremely efficient application of insecticide.