5 Reasons For Yellow Spots On Squash Leaves [How to Fix]

Squashes are a very popular and juicy vegetable that people love to grow in both summer and winter. They are usually very fast-growing and vigorous plants. But they are quite a bit vulnerable to many diseases and insect pests. And these diseases and insects along with some environmental issues cause yellow spots on the squash leaves 

And now you must be wondering how you can get rid of the yellow spots from them? 

To treat them, let’s explore all the reasons beforehand so you can approach the right method of their treatment. Because the squashes are tender vines, any wrong measure can easily ruin their productivity. 

There are mostly 5 common reasons for yellow spots on your squash leaves. You have to look out for  Watering Problems, Lack of enough sunlight, Nutrient unavailability, Pest attack, and some fungal and viral Diseases

But the good news is this problem can be easily tackled with some calculated measures.  And in this article, I am about to discuss what can cause the yellow spots on your squash leaves and how you can effectively get rid of them. 

So, without making any delay, let’s get started-

Causes and Solution of Yellow Spots on Squash Leaves

Spots on Squash Leaves

1. Not Enough Water

Squashes are basically very heat tolerant plants. However, they need watering at regular intervals during the dry periods otherwise the squash production will be drastically reduced. 

When your squashes are lacking water for a long time their leaves will get yellow spots from around the margin. These spots will gradually enlarge and turn the whole leaf yellow and later the leaves will brown. 

Control Measure

In this case, make sure your squash plants are getting about 2 inches of water every week. Sometimes when the temperature is exceptionally high, provide them a little more water than normal. 

During the rainy season cut back in watering depending on the intensity of the rain as we don’t want them to be overwatered. Because overwatered squash plants will also show the same yellowing symptoms as the ones that are underwatered. 

It can be hard sometimes to tell how much to water your squashes. Even though it seems like a normal thing, correct watering is very important to get healthy squashes from the plant. You can get a moisture meter and check whether the plant is in need of water(Our pick: Atree Soil Soil Tester Kits with Moisture, Light, and PH Test for Garden).

When watering, make sure you pour the water on the base of your plants. Do not water on the leaves. Because wet leaves might invite deadly fungal diseases. Try to water them in the morning so that any water splashes on the leaves can dry under the sun. 

2. Not Enough Nutrients

Squashes are heavy feeders. It means their soil needs to be rich in nutrients otherwise the plant will start to get the deficiency symptoms very easily. 

Mostly when they lack nitrogen the leaves start to get yellowish and blemish spots that increase upto the whole leaf.  Besides that, manganese, iron, and zinc deficiency can also cause yellowing of the leaves. 

Control Measure

The best way to combat this nutrient deficiency problem is by enriching the soil with fertilizer or compost before planting the seedlings or sowing the squash seeds. 

Meanwhile, keep fertilizing your plants at regular intervals with a well-balanced cucurbit fertilizer (our pick: Miracle-Gro 2000422 Plant Food). Also to get a better harvest, you can feed them some supplementary micronutrients like chelated iron through foliar application. 

3. Not Enough Sunlight

Squashes are tropical and warm weather-loving plants. Every day they need at least 6 hours of sunlight to stay healthy. Your squash leaves can get yellow spots like patches if they are shaded because of low light intensity. 

Control Measure

Make sure you grow your squash plants in an area where they can get more than 6 hours of sunlight. If you are growing them in small crates then don’t let them stay in a damp place. Rather shift those crates to a sunny side.  

And if you are using artificial light to grow them then keep them under light for 12-16 hours because these lights are not so much effective as the natural sunlight. 

4. Pest Attack On Squash

Squash bugs and whiteflies are the most common pests of squash that cause yellow spots on the leaves. Besides, aphids, spider mites, and leafhoppers can also attack the squash plants causing the same yellowing. 

Squash bugs feed on the leaves and show yellow spots as their bite marks. Gradually the spot color changes to brown and the area dry and falls off.

On the other hand, the whiteflies suck the juice from the leaves and eat up all the nutrients. As a result, the leaf area lacks nutrients and seems like yellow spots. In addition, the whiteflies secrete honeydew along with their feeding that brings sooty mold disease in the plants.

Control Measure

You can collect the squash bugs very easily because their size is about 5-6 inches. However, it’s not possible in the case of whiteflies because they are mostly very tiny and found in great numbers in the underside of the leaves. 

You can try to wash them off with a strong blast of water spray but this one is only a temporary solution. You need to get rid of them with an insecticide that effectively kills the pests while being safe for the fruits. (our pick: Natria 820040A Neem Oil Spray for Plants)

Always follow the insecticide’s label instruction because it will clarify how to use it and when to reapply again. 

Also to prevent their attack avoid using excess nitrogenous fertilizers. And avoid using insecticides when the temperature seems too hot. Because the squash plant leaves can be damaged by insecticide burn in the scorching sun. 

Another great way to control harmful pests is by encouraging beneficial insects such as ladybugs, and lacewings in the garden. Because they eat these pests and don’t attack the plants as well.

Try some of these effective home remedies to fight off these pesky pests:-

#Recipe 1:- Three-In-One Insect Spray Recipe


  • A small bulb of garlic 
  • A medium size onion
  • A teaspoon of dry pepper
  • A tablespoon of liquid dish soap


  1. Put the garlic and onion in an electric blender and make a paste
  2. After that add the pepper and dish soap in the paste and mix it nicely
  3. Then keep it aside for a few hours
  4. Strain the mixture with a fine cheesecloth
  5.  Now add two liters of water and pour it into the sprayer
  6. Spray on both sides of your squash plant every week.
  7.  Handle the mixture carefully as the pepper can irritate the skin. And keep it at a safe distance from the eyes.

#Recipe 2:- Orange Spray Recipe


  • An entire orange peel 
  • 500 ml of water


  1. Boil the water in a pot and then remove it from the stove
  2. Then put the orange peels in the hot water
  3. Cover the pot with a lid and let the water infuse the oranges
  4. After a few hours pick out the peels and put the infused water in a sprayer
  5. Spray twice a week on both sides of your squash plants. 

Note: Homemade recipes do not always show the best results. In some cases, they can burn your squash plant. This is why you need to check it on a small leaf before you apply it on the whole plant. If the leaf shows no abnormal symptoms then you can apply this to your squash plants. Otherwise, you have to dilute the solution with some water and give it another try. 

5. Diseases Of Squash

A downside of growing squash plants is, they are quite susceptible to certain diseases like squash mosaic virus, root rot, downy mildew, and fungal wilt.

Overwatering is the most common reason for bringing fungal diseases that make yellow spots on the leaves. Then later the spots merge and make the entire leaves yellow.

Fungal wilt and root rot can even cause the death of your plant if you don’t treat them immediately. On the other hand, downy mildew makes yellow angular spots on your squash leaves and later the spots turn brown.

And lastly, the squash mosaic virus is carried and transferred by insects like aphids, whiteflies, beetles, etc. The disease makes yellow mosaic patterned spots on the leaves. As the disease progresses the leaves get curled and distorted and eventually kill the plant within a few days.

Control Measure

When there is a fungal infection you need to be very quick to take some action. Since it’s a veggie plant we cannot risk using any fungicide that will be toxic to the squashes.

This is why choose the best non-toxic all-in-one fungicide to combat all of these fungal diseases(our pick: Natria 820040A Neem Oil Spray for Plants). Follow the label instructions very carefully to know how to apply it and when you apply it again.

If you suspect fungal wilt and root rot uproot your plant very carefully and discard the diseased root portion after that treat the roots with the suitable fungicide.

If your squashes are infected by the squash mosaic virus, then you have to stop the insect infestation as early as possible. Treat them with the best insecticide on a regular basis. In this case, prevention is the better option because the ones that become infected by the virus can’t be revived that easily.

In addition, don’t crowd your plant in a congested space as it will increase the chances of fungal and viral attacks. Also always clean the garden tools with rubbing alcohol before working with them.  And while watering be careful not to wet the leaves, especially in the cool and humid weather. 

Since root rot is a soil-borne disease so to prevent it, make sure you disinfect the soil with a good fungicide before planting the squashes. More importantly, don’t plant the squash in the same area for several years.

If you are willing to put in some effort you can make your own homemade fungicide very easily. Here are the recipes below: 

#Recipe 1:- Baking Soda Fungicide 


  • One and a half tablespoons of baking soda
  • 2 teaspoons of liquid soap
  • 2 teaspoons of any cooking oil 
  • A gallon of water


  • Combine all these in an electric blender then pour it into a spray bottle
  • Spray it on both sides of your squash plant twice a week until the disease is fully treated

#Recipe 2:- Vinegar Spray Recipe


  • 2 tablespoons  of apple cider vinegar 
  • A gallon of water of water
  • A teaspoon of mild  liquid dishwashing soap


  • Mix all the ingredients very well preferably in an electric mixer
  • Spray on both sides of the infected squash leaves twice a week until the fungal  problem is solved

Frequently Asked Questions (FAQs)

1. Should I remove yellow-spotted leaves from squash?

Do not remove the leaves at bulk because the plant makes food from the leaves. Also through the removed parts, many bacteria and viruses can enter and cause diseases.

2. Should I water squash every day?

You do not need to water them every day. Watering them deeply just once a week is enough. However during monsoon water every two weeks.

3. Can the yellow leaves of squash turn green again?

If it’s due to watering or sunlight issues then the leaves will turn green when they get what they need. But diseased or insect-infested yellow leaves are highly unlikely to turn green again. 


To get a wholesome quality of squash in your garden you have to give them some support. When they have yellow spots on their leaves it means they are suffering and trying to ask for help. 

They need proper nutrition, adequate water, and proper sunlight. Aside from that they need protection from diseases and pests otherwise the squashes you will harvest will not be of good quality at all.

I have tried to include every necessary information about how to identify the reason and treat the yellow spots on your squash leaves. I hope this article helped you fix the problem with ease. 

In the same way, you can apply the exact measures that I mentioned above for your tomato, zucchini, and cucumber plants too.

Squash are cucurbit plants with many species variations, including the popular zucchini. These plants produce rich-green foliage with vibrantly colored vegetables that range in color from yellows and whites to greens and grays.

Squash are often categorized as winter and summer squash with winter squash being harvested in the summer and stored for eating in the winter. Both types are cold intolerant and susceptible to various diseases that can quickly yellow the plant’s foliage and impact the vegetable quality.

Leave a Comment