My tomato plants stems had mealy bugs and with in an hour of my notice I started to spray neem oil liquid soap water and the plants now looks very bad and the leaves looks very dull. Will the leaves again regrow or the plant will die? I have applied this before also when my plants did not have mealy bugs but I never saw this change. Please tell me as what can I do now?
There should be no worries using Neem on tomatoes, Penn State U says so. The only catch is to apply it exactly as the instructions recommend.
In applying the Neem you will have applied two ingredients, the soap and the Neem oil. The soap is used as a spreader to allow the oil to stick to the leaf. Tomato leaves are covered in tiny hairs that will resist the oil if the soap is not present. You leave the oil in place for the bugs to eat and croak.
So we can speculate on why you see the dullness: because of the tiny hairs, what you normally see will be light reflections from the hairs along with the leaf surface. Now with the Neem in place the hairs are somewhat covered and the Neem itself will be mixed in. Think back to what kind of soap you used, there are chemical soaps that will harm plant surfaces and need washing off, but in the case of the Neem really it needs to be left on for the bugs to chow down on.
If you used innocent soap and followed the mixing instructions then just sit back and be patient, all will be well.
Neem has another use besides pesticide. Neem is also used for spraying leaves to make them shine, more glossy, gets rid of dust. I'd never use it this way, ugh. I hate the smell of Neem. But even on hairy tomatoes your plants should look better not duller.
What soap did you use? How much did you mix in the mix with the Neem? How much Neem? Grins, did you read the label 5X each and every time you use any pesticide? That was what they harped in our Pesticide Licensing seminars. Constantly. I read it once every single use, I am bad with instructions.
I've never needed a spreader/sticker with Neem. I'd put my plant in the shower and let it have a good rain or if it is outside use a water wand to give your tomatoes a shower. Wait a few days and if you see live mealies spray again without the soap. You might have used too much soap and it left a sticky residue which could block the gas exchange stomata beneath the leaves. I'd wash the plants off and wait for the mealies who already have had a meal to die. They don't die that quickly. Let us know what and how much soap you've used.
Don't spray Neem during the day when beneficials and bees are around. Some Neem products say it is safe for bees but don't believe it. Avoid spraying Neem on the flowers. Use a paper plate and wear gloves. Conversely you don't water in the evening or at night because you want your plants dry going into the night time to reduce fungal problems.