Vine Weevil Spraying

Sprayed Rhododendrons and Pieris(Forest Flames) with 'Thiacloprid' ('Provado Vine Weevil Killer 2'). The idea here is to kill the adult weevils before they lay eggs and before they do too much cosmetic damage to the plant leaves (adult Vine Weevils chew out semi-circular chunks from the leaf edges).

Although it might still be a little early, I don't want to give them any chance. I have sprayed up under the underside of the leaves so that the chemical will dry on there, not get washed off, and produce lasting protection. This chemical is also systemic (it is taken into, and moves around, within the plant), so spraying the underside also helps uptake, because it is sprayed directly onto the leaf pores through which it can enter the leaf.

It might still be a little early. I find that adult Vine Weevils prefer tender young leaves, which are only just developing on the Pieris but only develop after flowering in the Rhododendrons. At this time it is difficult to spray without some spray getting onto the flowers and thus poisoning the bees. By the time it is safe to spray, it is too late; the damage has been done.

Ideally, I like to spray the leaf buds just as they are opening. This way, the chemical is on the leaf edges where the weevils feed.

This treatment is not the standard one, which is pouring the insecticide onto the roots to kill the grubs (which can do the real damage). But I find the cost of doing this to be prohibitive. Spraying the leaves is far more cost-effective, provided all the adults can be killed.

However, it is worth treating pots of Fuchsias and other vulnerable plants by douching the roots.

This chemical provides long-lasting control for up to 2 months.

I will treat them again in a few weeks.