Pyrethrum-rotenone spray

Pyrethrum-rotenone sprays also have some effect on other tortrix moths. 

DIRECT. Pyrethrum-rotenone sprays have some effect on noctuid moths. At high temperatures Bacillus thuringiensis formulations also have some effect on noctuid moths (50% effect). 

DIRECT. After the damage threshold is exceeded, a pyrethrum-rotenone spray should be applied at temperatures above 12°C. If very early treatment is necessary because of the high population density, a second spraying may sometimes be needed, as beetles move continuously from the winter hiding-places to the apple trees until the eggs are laid. 

DIRECT. Application of pyrethrum-rotenone sprays after the damage threshold is exceeded. 

CONTROL. The pyrethrum-rotenone sprays used against the apple blossom weevil are also effective against the apple fruit rhynchites. The control deadline is much later, however (May-June). 

DIRECT. If there has been infestation in the previous year, the first spraying must be done in September, immediately after the harvest, using pyrethrum-rotenone sprays. The spraying must be repeated if necessary. It is important that the weather is warm and fine. 

A pyrethrum-rotenone spray should be used against the adult sawflies before flowering (when flight increases and the first slits are found) if there has been very severe sawfly infestation the previous year and large numbers of indentations have been found in the calyx region. 

DIRECT. The value of control measures depends on the level of infestation in the previous year. Treatment should be carried out if there was severe infestation in the previous year and blossom production is slight. Pyrethrum-rotenone sprays have some effect. 

Areas of application Mode of action How obtained Remarks Codling moths, tortrix moths, aphids, leaf miners Contact insecticide Ryania is obtained from the wood of Ryania speciosa Broad spectrum of action More persistent than pyrethrum-rotenone sprays Poisonous to fish Not registered in the EU at present... 

Pyrethrum-rotenone or Bacillus thuringiensis sprays have some effect. 

For four years, Muller synthesized his own compounds and almost single-handedly screened them for their effect on houseflies. They were known to be transmitters of intestinal diseases like dysentery, and it was speculated at the time that they might spread polio. Muller built a cubic-meter glass chamber for insects and sprayed compound after compound at them. As soon as one compound seemed promising, he searched more carefully among its close relatives, using the natural insecticides, rotenone and pyrethrum, as controls. 

At first, Geigy s biologists were puzzled because the insects sprayed with DDT did not die immediately. Accustomed to the quick action of pyrethrum and rotenone, they dismissed Muller s discovery as unimportant. They did not realize that DDT s long period of activity could be far more important than sheer speed. In the parlance of insecticides, DDT had slow knockdown but sure kill. Surfaces sprayed with DDT in 1941 and stored under dust-free laboratory conditions were still toxic to insects seven years later. 

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