Looking for a topical insecticide for mealybugs

[Shane]

I'm looking for a non systemic treatment for mealybugs. The last time I applied imadacloprid, it really wasn't effective (in contrast to other times I've used it). I don't know why but maybe it was the weather. It was back in April when we were having very hot sunny days alternating with cold cloudy days. That seems to stress the plants and possibly they all went dormant in response

Anyway I now have a bunch of dormant summer dormant plants with mealybugs. I know soil soaks won't work on them and I'm hoping to limit the damage by applying a topical insecticide. I've neem oil, and I don't think it works (and it's bad for some plants), soap which also didn't work and damaged some of my plants, and alcohol. Does alcohol work? Does anything work?

[Steve Johnson]

I'm looking for a non systemic treatment for mealybugs. The last time I applied imadacloprid, it really wasn't effective (in contrast to other times I've used it). I don't know why but maybe it was the weather. It was back in April when we were having very hot sunny days alternating with cold cloudy days. That seems to stress the plants and possibly they all went dormant in response

Anyway I now have a bunch of dormant summer dormant plants with mealybugs. I know soil soaks won't work on them and I'm hoping to limit the damage by applying a topical insecticide. I've neem oil, and I don't think it works (and it's bad for some plants), soap which also didn't work and damaged some of my plants, and alcohol. Does alcohol work? Does anything work?

If BioAdvanced 3-in-1 still has Imidacloprid in its formulation, go with the bottle that has a built-in nozzle for spraying. Believe it or not, Imidacloprid is fairly effective as a transdermal spray, although you should spray only at night when your plants' stomata are open for transpiration. Only downside is that the transdermal effect lasts for about 30 days, so you'll need to spray again when it wears off.

Regarding your problem with the systemic, April wasn't a good month for it -- if I give my cacti a preventative soil soak (may not feel the need to do it this year), it'll be sometime next month when the weather is consistently warm enough.

[Shane]

Thanks for the advice Steve! I didn't know imadacloprid was transdermal, I've only used it as a soil drench

I haven't done my cacti this year, the plants it didn't work on were all winter active succulents. I thought it wasn't too late a month ago but the results say otherwise

The bugs haven't really gone for my cacti too much yet knock on wood. Minus a Ferocactus that's absolutely covered

[Download]

Just select a pyrethroid such as permethrin. I've used both permethrin and tau-fluvalinate and found both work well. Permethrin was cheaper though.

[Shane]

I have an update here, I tried an Imidacloprid spray and it really helped. The problem has been greatly reduced in size and I believe can soon be eliminated (for now...). The mealies did come back in some (maybe 10-20%) of the plants. This I believe is due to:

1. The spray not quite reaching every part of every plant. I tried very hard to get good coverage, but a lot of the Echeverias, etc, have many nooks and crannies and realistically I don't think I got them all
2. Poor vector control. I believe some of the new mealybugs entered from outside my collection. Until last week I was keeping most of my plants at somebody else's house and didn't have much control over things that could have prevented this
3. Lack of vigilance on my part. My plants were not near where I lived and I did not go over and check on them as often as I should have

Overall, I'm very happy with the results I got. The specific product I used was bioadvanced rose and flower insect killer. It was a little pricy compared to buying the concentrate and hopefully I can find a refill rather than having to buy a whole new one. Definitely worth the money either way though

[eamnav215]

Have you ever heard about enthomopathogenic fungi as a biocontrol?
I'm from a tropical country and have started applying Bauveria bassiana as well as Metarrhizium anisopliae for biologic control. Once you have stablish populations of this fungi, they will regulate and parasite mealybugs and other potential parasites. And, since it is a living organisim it could reproduce itself and trive as a bioprotector. Besides, mealybugs can't develop tolerance to this fungi.

http://ipm.uconn.edu/documents/raw2/Usi ... .php?aid=5

[Shane]

Have you ever heard about enthomopathogenic fungi as a biocontrol?

I have not. This is intriguing and I think preferable to whack-a-mole pesticide application. Realistically, in my Crassulaceae there will always be mealies somewhere. They're just such a target. It would be nice to turn it from an acute to chronic problem. And my most mealybug prone plants aren't really fungus prone so I wouldn't have to worry about killing the good stuff with fungicide application

[Shane]

I have had great success using biological control for fungus gnats. I'm definitely going to give the fungus a try. Thanks for sharing. I had no idea it existed

[eamnav215]

I've had amazing results. But I'm not gonna lie to you, I still find some meallybugs from time to time, but really an application of Bauveria bassiana as well as Metarrhizium anisopliae plus a 10% application of a topical insecticide (to debilitate defences of any insect and help the fungi parasite more effectively) controls the situation. Give it a try, usually commercial products are developed for the control of insects in one's region.