Does anyone here use powdered sulphur on the leaves of their fruit trees? I read that it has insecticidal and good nutritive value. Ive used it on my sweet cherry trees, apple trees, and some on my plum trees. I’ve also read that it can damage some plants…
Years ago, I used to buy Pratts powdered orchard spray from Pennsylvania. It had Malathion, Para-Malathion, Captan and Sulphur as it’s primary ingredients, and it worked great. It apparently is no longer available. I’ve tried Neem oil spray, without much success… I have the outdoor fruit trees, and I have indoor trees, (mostly citrics). The indoor trees get scale insect so bad before Spring, that I am tempted to stop growing them. It’s a great struggle to pull out the alcohol and brushes to dislodge the scale. Sometimes the lemon trees will start dying back. If we don’t cut the die back off, then well lose the entire tree. I noticed that whenever I buy citric trees from the nursery that they’ve been treated with a systemic for pest control. I’m trying to show love to our pollinators, and to preserve them. Any thoughts? Denny in Columbus Ohio, zone 6b.
Scale and white fly have been the bane of my glass house plants. I use this mix i found on you tube : 2 quarts water 1 cup alcohol 1 Tablespoon peroxide 1/4 cup tea tree castille soap and 1/4 cup peppermint castille. Soak the plant and the soil. Kills scale, aphids and whitefly, mold and mildew. Spray every six days until under control. In my experience ants are a big factor in scale and mildew, I bait with powdered sugar and borax, cornmeal and in spring and summer hamburger with borax. It takes discipline to stay ahead and lord knows I have gotten cocky thinking i have eradicated all the boogies and slack off only to have them take over again. But when used consistently the plants are bug free and pretty. My glass house citrus love a good shower about once a month too. Dislodges anything unsavory and perks them up.
I use wettable sulfur on occasion, mostly as a dormant spray to help with mites and rust on figs. You have to be careful with it because it can burn the plants, and you absolutely cannot use it anytime before or after an oil spray or it will burn the plants. I believe the usual recommendation is at least a month between sprays, but don’t quote me on that.
I do use soap-based sprays indoors to control soft-bodied insets. It works, but you have to use it very often, get good coverage, and it’s probably best to also occasionally spray with just water to rinse the leaves off because otherwise the soap residue, house dust, and whatnot will build up. Use a dedicated insecticidal soap, don’t use regular soap–most soaps are very salty and if you use it often it can cause issues.
Conceivably, some sort of soap or oil-based “natural” spray (I’ve never seen a potassium-hydroxide tree personally, but maybe they have some in Castile where they make that soap, ditto for hydrogen peroxide trees) might control scale. Your best bet would be to spray very often throughout the year in the hopes of killing enough of the eggs and the larva that the adult population starts to shrink. You’ll be killing any and every other insect on your trees whenever you spray, including beneficial and pollinators, and any insects sheltering on the trees the first time it rains after each time you’ve sprayed are likely to be killed as well, but that’s the coast of using most natural control methods–they’re usually broad-spectrum contact killers.
As @Itchybee Itchybee mentioned, you might have some results if you actually control the ants instead of the scale itself. Homemade borax baits can be effective, I’d caution not to make them too strong or use them too much though as boron toxicity can be an issue with citrus. There are also baits you can buy online that have insect growth hormones as their active ingredient–most of them work by screwing up the ant larval development by overdosing them with juvenile hormones. Those don’t generally get counted as “natural” since the insect growth hormones are made in a lab rather than collected from bugs directly, and sometimes they are actually analogues rather than the exact chemical form of the hormone. Anyway, you’d want to try and figure out what kind of ants might be causing the issue since the kind of bait base will change depending on the kind of ant and what they forage for.
Lastly, you could technically spray nicotine tinctures, which are entirely natural and renewable. But if you do please be extremely careful, neo-nicotinoids have much lower mammalian toxicity than nicotine itself, so it’s a lot more dangerous to you to spray regular, natural nicotine rather than synthetic nicotine-like chemicals. Natural nicotine is a systematic herbicide and also just as toxic to pollinators as neo-nicotinoids, so the same precautions apply–never spray before or during flowering, and never spray a tree that has any broadleaved weeds or ornamentals growing nearby as overspray or rain runoff can carry the nicotine to those plants which would then bloom and kill pollinators.
Long term, you may want to work on building up a really rich, well-draining soil, and also getting a little bit of partial shade on your citrus plants. Citrus are very heavy feeders, and they do best in deep, rich soil that’s got a good shredded hardwood mulch layer on top–and keep in mind that they’ve got pretty large root systems so the mulch layer should extend well beyond the drip line. Citrus are also understory trees naturally, so unless you’re at a high latitude where they sun is much weaker, citrus are often healthier and less stressed if they get a bit of shade. They’ll produce a little less than in full sun most likely, but that also reduces the stress on the plants, and long term production should be better if the plants are healthy and growing well.
Me personally–I’d focus on the latter part. I’d use whatever commercial type synthetic insecticide works best for scale to get them under control, and instead put my efforts and money into drastically improving the conditions the plants are growing in.
Ah, just saw that you’re in Ohio. So you’re probably not growing in ground, and the sun is certainly not stressing your trees unless they’re spending too much time in a greenhouse during the summer or something.
Them being in pots gives you more options I’d think. But it also means there’s a higher chance your plants are getting badly stressed. Best of luck! My personal advice is still basically the same–do whatever is quick and effective to get the disease under control, and then put all your money and effort into making sure the trees are growing under the absolute best conditions you can reasonably provide. Perhaps that means repotting, fertilizing less but more often, automatic watering in the summer, brighter lights in the fall and spring, a humidifier in winter, etc. Hard to say what exactly they need, but odds are there’s more than a few things that could be improved.
Thanks for your great advice. My wife sprays water with dawn dishwashing soap and peroxide. And sometimes she sprays vinegar water. I’m afraid that the wine vinegar water could be toxic for the plants. If I use harsh chemicals, I try to do it before bringing the plants in for the winter. One or two separate sprayings of Malathion liquid, mixed with some powdered Imidan seems to help. This last year I made the mistake of trying to spray with Neem oil spray, and it didn’t work well.
The sulphur I’m referring to is not wettable sulphur, it is just powdered sulphur. Sulphur in the soil is apparently almost as important an element as nitrogen is. I’ve really not seen any burning yet, and it repels the ants on my Ranier sweet cherry trees.
Thank you for the spray formula… I do worry about our pollenators, especially with reports of 55% of honeybees dead this year. Some beekeepers are reporting 90% colony losses. We encourage mason bees wasps, yellow jackets and hornets too. It is very cool to see the wasps etc. patrolling every leaf of our apple trees. We love it! My wife has crown of thorn plants, and wasps are the main pollenators for them. Creation is amazing.