I noticed in the monthly eNews that the ongoing battle with Mealy Bug was mentioned & that "They're resistant to insecticide!"
Don't despair just yet as I purchased a different Provanto product & treated all my cacti last week with it which has been very effective.
I have a couple of plants where Mealy Bugs have been persistent. So I took great joy in inspecting them with a magnifying lens and observing them all as corpses.
Paul in North-east Scotland (Grampian Branch BCSS)
National Collection Rebutia, Aylostera & Weingartia (inc. Sulcorebutia). Also growing a mixture including Ferocactus, Gymnocalycium, Lobivia, Mammillaria, Lithops, Gasteria, Haworthia. http://www.rebutia.org.uk
Despite its claims of working for up to 8 weeks, I have found bugs on sprayed plants a week or two later. I'm not sure if they were newly hatched, or came in from elsewhere, or if I just have a resistant strain.
Thank you. And well done to Paul as the active ingredient is flupyradifurone. Looks promising.
Ralph, reading the information from Provanto, they only claim up to 8 weeks for aphids, not other pests. I always take those kinds of claims with an unhealthy dollop of salt!
Significant persistance of any plant/crop treatment chemical, even ones with remakably well-targeted effects such as flupyradifurone, are unlikely to be got through licencing at all easily.
No matter the claim, flupyradifurone, is used on food crops and if it persisted for long periods, it would be a commercial non-starter.
Davey246 wrote: ↑Thu Jun 02, 2022 8:43 am
Significant persistance of any plant/crop treatment chemical, even ones with remakably well-targeted effects such as flupyradifurone, are unlikely to be got through licencing at all easily.
No matter the claim, flupyradifurone, is used on food crops and if it persisted for long periods, it would be a commercial non-starter.
Indeed if very long-lasting wouldn't be available. However we don't really need a long-lasting pesticide; all we need is to break the production cycle of mealy bugs, i.e. kill the adults and juveniles, then also kill the next generation, anything that hatches out of eggs already laid. In mid-summer in a greenhouse, a cycle can be as little as 5 days so if a pesticide persists for a week or more it will probably be effective at that time of year.
Bad news from Ralph though, if mealy bugs are already resistant to it
Paul in North-east Scotland (Grampian Branch BCSS)
National Collection Rebutia, Aylostera & Weingartia (inc. Sulcorebutia). Also growing a mixture including Ferocactus, Gymnocalycium, Lobivia, Mammillaria, Lithops, Gasteria, Haworthia. http://www.rebutia.org.uk
I have always assumed that re-treatment every 4-5-6 days for a couple of weeks was essential. That said, I have been extremely fortunate in that I have never had mealy infestations, just RSM.
The very rare bought-in plant with mealies was easily dealt with.
If you read Wiki for the chemical, resistance seems unlikely, but never say never. It was also only recently licenced for use in the EU, so not at all long for resistance to build-up.
Most pesticides these days also have limits on how many times they can be applied in a growing season - e.g. 3 or 4, which also makes using sufficient repeat applications to ensure all bugs are killed off pretty tricky.
