Wendy M. from Hervey Bay, Australia
I'm wondering if your tomatoes are cracking and splitting AND THEN becoming infested with some type of grub, or if the grub is causing the fruit to split. In either case, yellowing leaves are a sign of stress. I'll describe some solutions for both cracks and grubs/worms and leave it up to you to try to determine exactly what is going on. Cracks that circle the stem end of ripening fruits or start at the stem end and run down the side, usually appear after a sudden growth spurt caused by an increase in soil moisture after a period where the plant has been too dry. Sometimes after cracks appear, insects can move in. In most cases, working to keep soil moisture levels as even as possible will prevent this. If droughts are common in your area, look for "crack-resistant" varieties to plant.
There are several types of caterpillars, worms or grubs that can attack tomato fruits. Tomato fruitworms are one of the most common. Signs include small holes on the surface of the fruit. The larvae of the fruitworm (also called corn earworm) are light yellow, green, pink or brown, with long spines and a lengthwise stripe. Adult moths lay eggs on the leaves of the plants or in the soil around it. The eggs hatch and once the larvae burrow inside the ripe fruit, they feed on it. Eventually it becomes rotted and hollow and collapses like a deflated balloon. Handpicking adult caterpillars and covering your plants with netting or floating row covers to prevent adult moths from laying eggs will help prevent infestations.
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By Margie Minard (Guest Post)10/02/2006
If you are a smoker, that could be the reason the leaves of your tomatoe plants are yellow. Even a little nicotine on the plants could harm them. Use gloves, or wash your hands well before handling the plants and don't smoke around them in the garden. I had real bad luck with tomatoes when I was smoking, and absolutely none after I quit. There may be a little too much water if they are splitting, and the grubs can be getting in there, then. I also plant an onion bulb and a marigold with each tomato plant, which keeps lots of bugs away. I use "Seven" on my plants when bugs do find them. Perhaps there is the equivilant to that in Australia. I don't use much of anything if I can help it, and that is the least harmful to mammals. Hope this helps. Once I heard that the ultimate act of faith is to plant a seed. Good luck and God bless.
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