I have a question does any one know if topping off my pots with crushed eggshells have any negative effect on my cacti?
My plan is to combat my mealybug problem with eggshells I know they die from simply walking on or near them due to the sharp edges and there soft skin.
I am also gonna bury a cactus in eggshell for 10 days to see if i can kill all the eggs that hatch I might have to leave it a little longer give them some time to crawl around.
Here is a picture of my first test it's hard to see but there are 3 mealybugs in the picture one is bleeding I will follow up and let you guys know how it goes unless any one can tell me that eggshells are bad.
Some cacti won't be impressed by the eggshells but I doubt you'll damage them in any short time. Some might even like it.
Killing adult mealies is a bit pointless since they hardly ever move. You have to kill the nymphs which are almost invisible tiny specks. Nymphs tend to hang out on the same plant so long as there is enough to eat, but they can also wander off to new homes. I doubt the eggshells will get them all.
You might also want to look for diatomaceous earth, a more effective killer than eggshells. Chemically it is almost inert, but a layer on every pot would slow down many pests. Mixed into the soil it would be very effective against root mealies.
Thanks for the info i have been using diatomaceous earth it's almost 1/3 of my soil mix. I dont use it as a top layer though. since i have moved my cacti indoors the mealies are popping up every day on different cacti. When i moved them in i spent 2 weeks cleaning them all with alcohol and they still came back. There is a ban on pesticide in ontario the only thing i haven't tried. I will have to go smuggle some in if this doesn't work.
I also do believe, that with either diatomateous earth or egg shells you will not achieve good control of mealybugs. These little devils are very hard to control, even with chemical insecticides.
Except for perhaps root mealybugs, the eggs are laid on the plant and the insect will spend all its life there. So covering the ground with sharp edged material would not do much good. The males are able to fly, the females are not. The nymphs (crawlers) are the invasive force you have to deal with and will move to other plants. This would in most cases require movement across soil or from one plant to the next, if those plants touch each other. A dense planting would make this much for likely. However, some of the crawlers could also be transported by air movement (wind) or splattered rain or washed off the plant by a deluge of water. In a controlled environment you can reduce these possibilities. The best way - excluding the use of pesticides would be a physical separation from other susceptible plants. The infested ones you could treat with alcohol, insecticidal oils, natural predators, etc.. Most likely this treatment or combination of the ones mentioned would be rather time consuming, requiring almost daily checks and repeated applications.
I have found that mites, mealybugs, aphids and scale insects are all very hard to control and eradicate. That is why I generally suggest using imidacloprid, a systemic insecticide, which is easily available to anyone, at least in the U.S.. However, I am always in favor of using biological means and non-toxic substances, if the job can be done this way.
I will follow up and let you guys know how it goes unless any one can tell me that eggshells are bad.
