White spots on pumpkin leaves most probably means that the plants have powdery mildew though there are other pests that can cause white spots. Most causes of white spots on pumpkins can kill them, so you need to get the necessary products to keep your plants safe.
To learn the necessary products to use for your plants as well as all the causes of white spots on their leaves, read this article.
- Why Are There White Spots on Your Pumpkin Leaves?
- How To Treat or Prevent White Spots on Pumpkin Leaves?
Why Are There White Spots on Your Pumpkin Leaves?
There can be white spots on your pumpkin leaves because of powdery mildew. That is the first thing that you should watch out for as it is the major culprit. Some other reasons why pumpkin leaves can have pale or white spots are insects and other pest attacks, and sunburn.
– It Could be Powdery Mildew
Powdery mildew is indeed the number one cause of white spots on your pumpkin leaves. Many other reasons listed in this article can lead to a powdery mildew attack on your pumpkins.
Powdery mildew is a type of fungi that attacks many types of plants. Will powdery mildew kill pumpkins? Powdery mildew kills plants but first makes them weak and turns most of their leaves white.
As soon as you see your pumpkin leaves turning white or spot white mold on pumpkin stems, the first thing that you should think of is powdery mildew. Powdery mildew on pumpkins should make you take urgent action as it can easily spread to other plants.
– Downy Mildew
Just in case you see white or pale mold-like spots on your plant leaves, the culprit could also be the downy mildew species. The leaf spots of plants attacked by downy mildew resemble those of powdery mildew, but they are distinguishable as they are usually pale and not completely white. Just like powdery mildew, downy mildew can harm plants.
Downy mildew starts from one leaf in a plant and spreads to the rest of the leaves. You will likely find it in the upper leaves of the plants. If you are growing your pumpkin plants near cabbages and broccoli plants, there is a high chance that the pathogen is coming from those plants.
– High Humidity
Just in case you see your pumpkin leaves turning white or developing white spots, use a hygrometer to check the humidity of the garden or room.
High humidity can encourage powdery mildew, other fungi, and bacteria to grow quickly. Note that the attack on your pumpkins by harmful microbes may lead to spots of different colors, not just white.
Aside from the white spots on the leaves, the leaves may also feel moist when you touch them. Asides from the level of humidity, you should also check how often you water your pumpkin leaves because if too much water remains after watering, it can attract fungi.
– Sunburn is the Problem
Sunburn can lead to white, pale, or yellow spots on pumpkin leaves, so you want to check if your pumpkin plants are receiving more sunlight than they need. Sunburn usually occurs in summer, especially if you are not growing your pumpkins under a shade cloth. You should see spots on the upper leaves of the plants.
If the spots are occurring in random leaves, the problem may not be sunburn as sunburn mostly affects the leaves nearest to the sun. Asides from seeing the leaves turn white, another sign of sunburn is that the edges of your pumpkin leaves will look burnt.
– Bacterial Infection
Bacteria such as bacterial leaf blight can attack plants and make their leaves turn yellow, brown, white, or pale.
Bacteria are very harmful and they can spread quickly to other healthy plants, so you need urgent actions as soon as you see white spots on your pumpkin leaf. While there could be white spots on the leaves, the spots will turn yellow then brown or black if the plant is truly attacked by bacteria.
Bacteria usually attack plants that are not growing in the right conditions as the plants are not strong enough to fight them. This means that you should check the temperature, humidity, and watering rate if your plants have a bacterial attack.
– Plant and Soil Are Nutrient Deficient
Pumpkin leaves turn yellow or pale when the plant does not get enough nutrients, especially nitrogen. Well, the paleness of a leaf will start as spots before the entire leaf loses its coloration. If the problem is nutrient deficiency, you will notice that the bottom or older leaves turn pale before the upper leaves.
Pumpkin plants in their vegetative stage (i.e. the stage when they grow a lot of leaves) need a lot of nitrogen, so if it is not provided, their leaves will lose their color. Some other nutrients that can lead to pale leaves when your pumpkins do not have enough are iron, potassium, and sulfur.
– Insects and Other Pests
Some white insects that attack plants are whiteflies, scale insects, and aphids. You only need to carefully observe your pumpkin plants to check if the spots are mobile or immobile. Also, the location of the spots matter.
If the spots are very close to and concentrated around the petiole of the leaves, it could be insects or mold. However, if you can find the spots on the underside of the leaves, they could be scale insects.
Many of these insects that live on plants do not create bite marks on the plants, so you can’t quickly tell that your plants are being attacked. Well, aside from the visible white spots, you will notice that your pumpkins are weak.
– Could Be Paint or Something Else
What if you are just worrying over what could be painted? If you recently painted your garden fence or you have some buckets of paint in your warehouse or garage, there is a high chance that your kids or pets painted the leaves. Carefully observe the pumpkin leaves and check if the white powdery spots can easily peel off.
Painted leaves will smell like paint, so smell the leaves. Asides from paint, other things that do not harm plants but could produce white spots on plant leaves are dust and dirt.
How To Treat or Prevent White Spots on Pumpkin Leaves?
To treat or prevent white spots on pumpkin leaves you can use myriad methods – from fungicides to potassium bicarbonate. Here is how to prevent or control powdery mildew, other plant diseases, and other causes of white spots on pumpkin leaves.
– Buy Fungicides From a Store
It is not difficult to prevent powdery mildew or treat powdery mildew disease in plants, but you need to be extra careful the first time your plants get attacked. The best way to treat the fungi is to buy plant-safe fungicides from a store nearby. Ensure that the product you are buying is proven to work against powdery mildew.
Treating powdery mildew in plants can take from a few days to months, depending on the number of plants attacked and your planting culture. If the humidity level remains excessively high and there is no proper air circulation, it could be hard to get the mildew off your pumpkins.
– Make Use of Potassium Bicarbonate
This chemical compound which you can buy in any gardening store nearby is very effective against fungi. It does not matter if your pumpkins are attacked by pumpkins or any other fungi, you can make use of potassium bicarbonate as it is a generic compound that so many fungicide brands make use of.
Just ensure that you apply the compound on the leaves that are attacked by fungi. Also, you can spray it around your plants to prevent any fungal attack.
If one plant is attacked in your garden, treat it with the compound then spray the compound on other healthy plants so that the fungi do not spread.
– Make Use of Baking Soda
Baking soda is a product made of sodium bicarbonate which is a compound that is very effective against fungi. You only need to spray the baking soda powder (or a mixture of water and the powder) on your plants with fungi and see how the fungal attack will disappear.
It is also a good practice to prune your pumpkin leaves affected and spray the cut stem with the baking soda product.
– Apply Neem Oil or Other Types of Horticultural Oils
Horticultural oils are oil-based pesticides. These oils are somewhat better than regular pesticides as they tend to last longer on your plants as well as have more concentrated pest-repelling properties. A very common type of horticultural oil is neem oil which a lot of gardeners worldwide make use of to repel insects and other pests.
Spray the soil on your pumpkin leaves with pests. Do so in the morning or evening and never in summer’s afternoon as it can be too hot. Also, do not spray the pumpkins in the fall and ensure that the pumpkin leaves are dry before you spray them.
– Grow Your Plants on a Trellis
Pumpkins and other climbing or trailing plants need to grow on trellises or any other support such as a cage or long stake.
Asides from giving their leaves more access to the sun, growing your pumpkins on support helps them to keep their leaves off the soil. There are so many pathogens in the soil, so trellises help to keep your pumpkin leaves safe.
Every pumpkin plant should have its support and ensure that you properly space each plant. Also, do not fail to water the leaves above when watering your pumpkins so that they do not get too dry or sunburnt in the summer months.
– Regularly Feed Your Pumpkins
To prevent your pumpkin leaves from becoming white or getting white spots due to the deficiency of nutrients, you should feed them regularly with a nitrogen-rich fertilizer.
Well, the growing stage of the pumpkin plant determines what type of fertilizer you should use. Note that the pumpkins growing leaves need more nitrogen while those that have started flowering or fruiting need more potassium and phosphorus.
If you do not want to use inorganic products for your pumpkins, you can quickly add compost, coffee grounds, blood meal, bone meal, and other types of organic nutrient-rich products into the soil.
If you want to grow your pumpkins in these organic products, please amend the soil a few weeks before you plant the pumpkins.
– Wipe Your Pumpkin Leaves Regularly
To keep your pumpkin leaves clean and safe, a good practice is to wipe their leaves with a cloth often. You can use a moist or dry cloth depending on what is on the leaves.
If the leaves look white because they are dusty or have white insects on them, you can use a dry cloth. However, if the leaves have stubborn dirt on them, moisten the cloth a little.
Wipe the leaves gently so that you do not ruin them. Also, do not leave the leaves dripping with water when you are done as overwatering can kill plants and even attract fungi and bacteria.
Now you know how to get rid of white spots on pumpkin leaves as well as what is causing the white spots.
Please remember the following:
- The first thing that you should watch out for if your pumpkins have white spots is powdery mildew.
- The best way to remove powdery mildew from your garden is to buy and use store-bought fungicides.
- You should regularly wipe your pumpkin leaves and keep them clean so that pests do not stay on them for long.
- Neem oil and other oil-based repellents are good insecticides, so ensure that you always have them nearby.
- Baking soda is a popular and effective product that you can use for fungal attacks on your pumpkins.
Now go to your garden, examine your pumpkin plants with white spots, and treat them with the tips that you have learned in this article.
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