Foliage Treatment Research Articles

Field-Plot Tests of Chemicals for Wheat Stem Sawfly Control

Nineteen insecticides were tested in the field for control of the wheat stem sawfly (Cephus cinctus Norton) as seed, furrow, broadcast, and foliage treatments. Six plant-growth-regulating compounds were added to Some of the foliage treatments. Control was directed mainly at the larval stage within the wheat stem. Some control of adults with the foliage sprays combined with growth regulators was evidenced, but on the whole these sprays and the broadcast treatments were not effective. Seed treatments with phorate and heptachlor at 1 pound and heptachlor epoxide at one-fourth pound per bushel gave control ranging from about 70% to 86%. However, phorate decreased the plant stand drastically at the dosage necessary to give control. Control with 25% dieldrin wettable powder at 2 pounds and 25% heptachlor wettable powder and 5% granules at 2 pounds per acre as furrow treatments ranged from about 71% to 96%. Heptachlor as a furrow treatment was the most effective and desirable method of control used in these tests.

SOIL INSECTICIDES FOR CONTROL OF THE TUBER FLEA BEETLE, EPITRIX TUBERIS (GENT.), IN THE INTERIOR OF BRITISH COLUMBIA

In the interior of British Columbia, single treatments of aldrin, chlordane, dieldrin or heptachlor applied before or soon after planting at 4.0, 7.5, 1.5 and 3.0 pounds of toxicant per acre, respectively, and immediately incorporated into the soil by disking or harrowing were highly effective against the tuber flea beetle. These soil treatments were more reliable, economical and convenient for controlling this pest than were the numerous DDT foliage treatments.

EFFECTS OF FOLIAGE TREATMENTS WITH GIBBERELLIN ON FORAGE YIELD OF ALFALFA, KENTUCKY BLUEGRASS AND WINTER WHEAT

Foliage of alfalfa and of Kentucky Bluegrass grown indoors, and of Kharkov winter wheat planted in springtime in the field, was treated with gibberellin solution before and/or after harvesting the forage once or twice. Visible elongation of leaves and of stems of the grass and wheat, but not of alfalfa, was induced by the chemical treatments. Treatments with 200 p.p.m. gibberellin had no distinguishable effect on weight of alfalfa. Such treatment of Kentucky Bluegrass, before the first cutting, increased fresh and dry weight at the first cutting, did not affect yield at the second harvest, and slightly increased the final total fresh weight. Corresponding chemical treatment, followed by one cutting at the end of the test, increased the weight of the grass as compared to controls cut either once or twice. Treatment with 200 or 400 p.p.m. chemical after the first cutting also increased the yield of the grass. Gibberellin treatment (36 p.p.m.) of wheat foliage harvested once at the end of the experiment improved the yield as compared to controls.

Studies on the effectiveness and utilization of systemic insecticides upon the injurious insects of citrus trees I

The author carried out some experiments, on the effectiveness of three systemic insecticides (Pestox 3, Systox, Sodium selenate) by soil and foliage application upon the citrus red mite (Metatetranychus citri MCG.), and toxicity of Pestox 3 and Systox to the 7-spotted ladybird (Coccinella septempunctata bnuckii MULSANT). Results obtained are summarized as follows. 1. When three systemic insecticides were wat-ered with water solution on potted Yuzu plant for control citrus red mite, Pestox was most effecti-ve, and the residual action of from 0.075 to 0.15 per cent water solution of this material was con-tinued for 3 months or more after the treatment. Systox was less effective than the Pestox 3, and the residual effect was lost after 11 or 12 weeks. Sodium selenate was little or no effect. The foliage treatments of Pestox 3 and Systox were less effective than their soil treatments. 2. When Pestox 3 and Systox were applied to the fo lige on yo ng Citrus tree in field, both Pestox 3 and Systox gave good control of the citrus red mite, and 0.075 per cent water solution of each material maintaining control for a peiriod of 6 or more weeks after treatment even under condition of heavily infestation of mites. 3. Pestox 3 was nontoxic to the 7-spotted ladybird (Coccinella septempunctata bnuckii MULSANT), but Systox was found highly toxic.

The Control of the Carrot Fly (Psila rosae, Fab.) (Diptera) with DDT.

(1) The proprietary emulsion “Guesapon ”, containing 5 per cent. DDT, gave an unsatisfactory control of carrot fly damage on a plot scale.(2) Treatment of the carrot foliage with this emulsion was more effective than treatment of the soil.(3) A I per cent. emulsion of DDT applied to carrot foliage in the field gave 100 per cent. mortality of carrot flies in the laboratory for 26 days after treatment and showed marked toxicity after a further 38 days.(4) The DDT spray deposits were very, resistant to treatment with water and remained active after death of the foliage. They were also very toxic and lasting on potato foliage.(5) Deposits given by ½ per cent. and I per cent. DDT emulsion were similar in toxicity and persistence. The ½ per cent. is, however, slower in action.(6) From a treated surface the carrot fly is able to acquire a lethal dose of DDT in a very short time, probably by absorption through the feet.(7) Emulsions containing ½ per cent. and I per cent. DDT applied to carrot foliage under cages in the field both gave 95 per cent. kill of carrot flies for a month after application. The treatments also gave a high kill of other insects.(8) Soil samples showed that the larval population and the damage was much lower in the treated than in untreated cages.(9) In a field trial 2⅓ acres of carrots were treated with ½ per cent. DDT emulsion at about 50 gals. an acre.(10) Sweeping showed a rapid decline in abundance of flies after treatment and high mortalities were observed. These features did not occur on neighbouring untreated carrots.(11) These effects lasted for some 21 days after treatment and a marked reduction of larval population and damage resulted.