Winter weevils

It is of particular importance to watch out for any signs of scab and mildew, as well as aphids, red spider mite and rust mite. Young splice or bnd grafts which are starting to sprout can be damaged by the grapevine weevil [Rhynchites conicus]. In some areas of Europe it is absolutely essential to check the nursery for voles before winter dormancy (catch them with traps or fumigate the burrows). 

Areas of application Mode of action How obtained Remarks Aphids, blossom weevils and other weevils, tortricids, winter moth, bugs, noctuid moths Contact, ingestion and inhalation insecticide Pyrethrum is produced from chrysanthemums and contains piperonyl butoxide as an additive which increases UV stability Very broad spectrum of action Not completely harmless to beneficials Pyrethrum is poisonous to fish Sprays consisting of pyrethrum alone are also commercially available (e.g. Spruzit)... 

In the spring, seed weevil and bladder pod midge may require control and in spring rape, or late winter rape, pollen beetle may also be a problem (Table 7.1). 

Hedin 458) has recently summarized factors that influence the biosynthesis of the boll weevil pheromone complex. Total synthesis was at a maximum during the summer and a minimum during the winter. In this study Hedin 458) did two types of experiments. The first series exposed 10-day-old adult weevils to a saturated atmosphere of a number of terpene hydrocarbons. It was found that only myrcene and limonene produced detectable amounts of oxygenated substances and that males produced more than females. No compounds isolated suggested that the weevils are capable of cyclizing alicyclic terpenes or their pyrophosphates. 

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