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MUSTARD OILS AND CONTROL OF THE POTATO‐ROOT EELWORM, HETERODERA ROSTOCHIENSIS WOLLENWEBER: FURTHER FIELD AND LABORATORY EXPERIMENTS
Author(s) -
ELLENBY C.
Publication year - 1951
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.1744-7348.1951.tb07856.x
Subject(s) - allyl isothiocyanate , biology , brassica , yield (engineering) , horticulture , white mustard , agronomy , steeping , peat , isothiocyanate , food science , ecology , biochemistry , materials science , metallurgy
Allyl isothiocyanate has already been shown to be effective against the potato‐root eelworm. Experiments are described in which this mustard oil, which occurs in the seed of black mustard, is compared with two similar substances; one, phenyl isothiocyanate, is synthetic, the other, phenethyl isothiocyanate, occurs in the roots of many crucifers, including black mustard. In hatching experiments, various concentrations of each of these oils in potato‐root excretions are used to stimulate eelworm cysts. The earlier results with allyl isothiocyanate are confirmed; it is also shown that the emergence of larvae decreases with increasing concentration of oil. An experiment in which different concentrations of oil are used in different strengths of root excretions showed that it is unlikely that there is any stoichiometric interaction between root excretions and mustard oil. Field experiments were carried out in different years and on different plots so that their comparison is difficult. But they appeared to show that talc is inferior to peat as a carrier for mustard oil. A comparison of the three oils on talc gave no significant improvement in yield, although plants treated with the allyl oil did best. In another trial with allyl isothiocyanate on talc, highly significant improvements in yield were obtained at dosages of 8 and 12 g. per row of ten plants, but the improvements were smaller than those reported previously for oil on peat. In a peat experiment on a plot giving the poor control yield of 4 oz. a plant, yield increased regularly with dosage and was almost trebled at 9 c.c. of oil per row of ten plants. On a plot with control yields of over 20 oz. a plant, 6 c.c. of oil per row increased yield by over 50%. It is shown that the increased yields are almost certainly due to a reduction in the severity of the attack, i.e. that the laboratory hatching trials ‘explain’ the field results. Although the cyst counts reported are by no means beyond criticism, they show conclusively that treated plants producing heavier crops of potatoes bear fewer cysts than control plants with lower yields. There is a suggestion that polyploidy may be induced by certain dosages of allyl isothiocyanate.