Neely Turner

Injuriousness of bordeaux mixture

SummaryAlthough Bordeaux mixture was known to reduce potato yields in the absence of pests, it has been demonstrated that the yields are also reduced where pests are serious. In such cases the dwarfing effect is masked by pest control.A method is described for separating the two mutually exclusive effects when operating on the same plots. It involves determining the graphic relation of pest attack to yield, and determining by interpolation on parallel curves, the yield of treated and check at equal levels of pest attack.The yield reduction is approximately 12 per cent on Cobblers, and 11 per cent on Green Mountains at median levels of pest attack.It does not follow that Bordeaux should be discarded. That would be catastrophic in war time because no adequate substitutes are in sight. We must search for ways of reducing the injury. These are as follows: begin spraying as late in the season as possible; spray as seldom as possible rather than as often; use lots of water in the fewer sprays with less copper per tank full, rather than less water and more concentrated; reduce lime to half the weight of the blue stone; and use dolomitic lime.

Organic fungicides for late blight in Connecticut

SummaryThis paper briefly reports three years research on new fungicides especially dithiocarbamates on potatoes in Connecticut. Dithane, first tested here in 1941, and reported in 1943 has long been under test for late blight of potatoes. It has succeeded in areas like Florida where flea beetles and leafhoppers are of minor consequence. Until the advent of DDT to control these two pests, dithiocarbamates could not succeed elsewhere. The data reported herein suggest that dithiocarbamates, particularly Dithane, are not much if any better than Bordeaux mixture in the control of late blight, but they do permit the potatoes to set a larger yield.It is suggested that this is due to a lower level of phytoxicity which, in turn, is due to low lime content of the Dithane.

The effectiveness of certain antidotes in counteracting the off-flavor in potatoes grown on soil treated with benzene hexachloride

ConclusionsActivated charcoal (1 ton per acre), when applied to benzene hexachloride-treated soil, showed a definite ability to counteract the characteristic off-flavor of benzene hexachloride in potatoes. It did not impart any off-flavor of its own to the potatoes.Alcoholic potash (1/2 gal., 0.1 N, per 60 sq. ft.) showed incomplete corrective properties. It did not impart an off-flavor of its own to the potatoes. Lime-sulfur, at the 25 lbs. per acre level, had some antidotal effect, but it imparted an off-flavor to the potatoes which would make its use objectionable.Lime (5 tons per acre) and ferric chloride (1 ton per acre) were not effective as antidotes, and in addition, they imparted an objectionable offflavor to the potatoes.

Standardized Oil Sprays

This paper suggests that viscosity, volatility and unsulfonatable residue determinations be published in papers giving results of tests of oil sprays.