Soil that is too low in iron, sulfur, or manganese can leave your plants with yellowing leaves, especially in new growth.Nutrient deficiencies cause other problems for your zucchini plants as well, including blossom end rot. Fungicides are going to be completely ineffective in these cases. The cucumber mosaic virus is one of the most common diseases that plants might succumb to. That is why you need to make sure that all exposed surfaces are covered with the insecticidal soap. Why Are My Zucchini Plants Turning Yellow? If you notice the plant infection, you can limit the spread by cutting off the affected parts of the plant. Cucumber beetles are usually responsible for carrying the spores that are found in the soil into the plant. In some cases, the zucchini will be stunted and may be misshaped. Another very common pest that is going to affect your plants is the spider mite. Plants that are not properly pollinated will usually develop less fruit, and you will notice that the zucchini turns yellow and will drop prematurely. Thankfully though, there’s a cure for the spider mites. The virus is transmitted through these tiny insects which leads to stunted growth as well as relatively poor development of fruit. Does the yellowing start at the edges of the leaf, in the middle, or in patches? There are several symptoms of poor pollination that you should look for. Do large leaves seem to be more affected, or new growth. While larger pests chew holes in leaves and cause obvious damage, tiny insects like spider mites and aphids cause more subtle problems. The zucchini plants can also be affected by the Fusarium wilt. Because zucchini are heavy feeders, they need lots of nutrients in their soil to draw upon. These tiny mites know how to hide properly and you are going to face quite a bit of difficulty in getting rid of them properly. They love feasting on the spider mites, and it won’t be long before the entire population is cleaned out from your plants. Soil that is too low in iron, sulfur, or manganese can leave your plants with yellowing leaves, especially in new growth. The only thing that you can do is to remove the damaged plants and clean the area. I would purchase a bag of potting soil and replant the zucchini into the new soil. Keep in mind that once the plant is infected, there is no way to cure it. I’ll share what I learn as I develop my green thumb. As they attack en masse, they drain nutrients and leave scars which cause leaves to yellow and wither. You will notice that the yellowing will usually occur from the end of the fruit (where it blossoms from) and then moves down toward the stem. Plant Diagnostics: Zucchini Plants Turning Yellow, Treating Powdery Mildew in Zucchini Plants, Preventing Powdery Mildew on Zucchini Plants. It’s best to turn the soil as well. You will need to make sure that the plant gets its intake of nutrients, and you will have to regularly water the zucchini plants as well. This is a fungal disease that tends to affect the vascular tissue of the plant. One common cause of yellowed leaves is poor soil. You might notice that the plant is green and leafy, and even produces flowers, though the zucchini might be turning yellow. I can't tell if I'm having a problem with insects, nutrients or disease. Aphids leave behind a sticky black residue on the leaves, while spider mites weave trails of silk. Because zucchini are in the same family as cucumbers (Cucumis sativus), cucumber mosaic virus can... Spider Mites. Potting soil is good for container gardening because it is lighter than garden soil. In some cases, it might wither and even drop from the plant outright. Spider Mites. If you want to make sure that your plant does not get so easily infected, you should consider planting the disease resistant variants. While there is absolutely no way to reverse the yellowing, you should know that there are ways to prevent this from happening. Once the plant gets infected, you should know that there is no definitive cure for it. If you notice any signs of aphids, you can make use of neem oil as well as insecticidal soap. The spider mite usually sucks the sap from the leaves of the zucchini plant. Are there visible insects or insect eggs on the plant? As the name suggests, the cucumber mosaic virus also affects cucumbers in the same family. If you want to know specifically which nutrients your soil lacks, contact your local garden center or extension office to find a soil-testing lab. The best way to get rid of these mites is to treat the plant with an insecticidal soap. Over watering can cause chlorosis. In some cases, the zucchini leaves might be turning yellow as well. The first signs of the disease include yellowing leaves of the zucchini plant, along with the veins. In the world of horticulture, this is known as fruit abortion. Hi! Happy planting! Many people who like to grow zucchini are often disturbed and disappointed that despite taking so much care about their plants, they are unable to get a good harvest. It’s worth the time and effort to prepare your soil by tilling in compost before you start planting. Before delving into what could be wrong, take a moment to assess your plants. Because zucchini are heavy feeders, they need lots of nutrients in their soil to draw upon. Cucumber Mosaic Virus: As the name implies, this disease doesn’t just affect zucchini, but a whole range of plants in the cucumber family. My name is Lisa, and I’m on a mission to expand my plant knowledge. This is caused due to the aphids which start to feed on the underside of the leaves. Often undetectable at first glance, spider mites suck the sap from … It is commonly spread by aphids, and can survive the winter in the roots of plants. Press Esc to cancel. The Practical Planter also participates in programs from ShareASale and other sites and is compensated for referring traffic and business to these companies. It is caused by the presence of insect pests. If you see signs of infestation, treat them quickly; insecticidal soap is effective against both these pests, and largely safe for beneficial insects. The zucchini is one of the most popular plants that people like to grow at home. Type above and press Enter to search. For instance, if there is a bit of rain or high winds in your area, the pollination will reduce dramatically.