Variety of infections and diseases occur in cauliflower plants. There can be a variety of symptoms occurring that let us know what caused the infection and thus, we can find out an effective solution to it. One of these problems includes occurrence of holes in cauliflower leaves. If your plants are suffering from a similar problem, then here you will find out the reason as well as the solution to this problem.
What Causes Holes in Cauliflower Leaves?
Occurrence of holes in cauliflower leaves can possibly occur due to pests. Pests can destroy plants leading to various symptoms, one of which is holes in the leaves. Here is a list of pests that cause holes in cauliflower leaves:
#1 Beet armyworm Spodoptera exigua
Holes observed in foliage of cauliflower in this case are singular or closely grouped, irregular to circle shaped. Leaves also develop a skeletonised appearance due to heavy feeding by larvae. Shallow and dry wounds appear on fruits. Egg clusters covered with whitish scales that look cottony or fuzzy appear on the leaves.
Young larvae are pale green to yellow, while adult ones are darker green. They also have a light line running on their body and pink or yellow on the underside of the body.
They can go through 3-5 generations in a year.
Beet armyworm can be controlled with organic methods like biological control by natural enemies which act as parasites on the larvae. Bacillus thuringiensis can also be applied to get rid of larvae.
Chemicals can also be used to control the spread of Beet armyworm. However, the use of chemicals may not produce effective results.
Also Read: How Long Does Cauliflower Take To Grow?
#2 Cabbage Looper Trichoplusia ni
Symptoms caused by infection from cabbage looper include large or small holes in leaves. The caterpillars causing holes in leaves are pale green in colour with white coloured lines on both sides of their body.
The way of moving by forming an arch helps in distinguishing cabbage loopers from others. These creatures lay eggs under leaves near the leaf margin.
These can easily be identified because of the characteristic ‘looping’ movement. They arch their body and back portion moves forward to be in contact with the front portion from the inner side.
Usually mother nature checks looper populations by natural enemies. You can handpick cabbage loopers to get rid of them from your plants. You can use Bacillus thuringiensis as a biological control.
Effective and appropriate insecticides can also be chosen for looper control. There are some specific insecticides that are effective in this job.
Also Read: Why Holes in Radish Leaves?
#3 Diamondback Moth Plutella xylostella
Diamondback moths have young larvae that feed on the upper as well as lower surface of the leaves. Small holes can be found on the underside of the leaf initially.
Older larvae form large, irregularly shaped shot holes on the lower surface of leaves. They do not affect the upper side of leaves.
Larvae of diamondback moths are small and tapering on both ends. They also have prolegs on the rear end of the body. It forms a V shape making them distinguishable.
Larvae get mature in around 10-14 days. They spin a cocoon around themselves on leaves or stems to form pupa.
The larvae can be controlled by using organic applications like Bacillus thuringiensis or entrust. Chemical insecticide can also be used to get rid of diamondback moths but it is only necessary when larvae are damaging growing tips of plants in the process.
Also Read: Why My Broccoli Leaves Turning Yellow?
#4 Flea Beetles Phyllotreta cruciferae
Small holes or pits in leaves are observed in cauliflower leaves. It gives a characteristic ‘shot hole’ appearance. Young cauliflower plants and seedlings are more susceptible to flea beetles than older ones. Severe damage from flea beetles is lethal to cauliflower plants.
Flea beetles are dark colored beetles with a shiny appearance. Whenever they are disturbed they jump.
Flea beetles go through 2-3 generations in one year. They multiply in plant debris, soil or on weed species nearby.
In places where flea beetles are a constant problem, a physical barrier can be created using floating row covers. It avoids contact between flea beetles and plants.
Also, seeds can be planted early before the expected time of flea beetles becoming a problem. Mature plants are less susceptible to damage from flea beetles. There are a variety of crops that are harmful to beetles like cruciferous plants.
Another management technique is the usage of a thick layer of mulch. It prevents beetles from reaching the surface.
Diatomaceous earth oils like neem oil can also be used to get rid of flea beetles. Next, insecticides containing carbaryl, spinosad, bifenthrin and permethrin provide effective control for beetles.
#5 Cabbage Worm Pieris rapae
Large ragged holes appear on leaves and are also bored in the head of cauliflower. Green brown feces of insects can be seen on leaves. The causing agent is a caterpillar with a green and hairy body. It has a velvety appearance and yellow or orange stripes on the body. They are comparatively slow moving caterpillars.
The larvae of caterpillars feed on plants and can be distinguished easily from others due to their sluggish way of moving. If the infection on plants is in huge numbers, it can damage plants extensively.
You can handpick caterpillars form the plants and destroy or get rid of them. Scrape eggs from leaves before hatching. If a plant is heavily infected then it is advised to use insecticide.
How to Protect Cauliflower Plants?
Growing cauliflower requires you to pay attention to various things like heat sensitivity of the plant, frost sensitivity, pests, water and much more. Protecting cauliflower plants is essential to keep them healthy and in good condition. Let’s learn some ways to protect cauliflower plants from a variety of problems-
Protection from Pests
Pests are the main creatures that can cause trouble and damage to cauliflower plants. They destroy foliage badly and cause damage enough to kill the whole plant. So, opting measures to protect from such creatures is necessary.
The creatures that destroy plants include cabbage worms, flea beetles, cabbage root maggots, cabbage aphids, slugs snails, etc. you must be familiar with some of them now.
To protect cauliflowers, use row covers. Row covers can protect cauliflower plants from cabbage worms, flea beetles and root maggots. Cabbage worms can be removed by hand from plants.
Sprays can be used to get rid of aphids. Use neem oil after applying a stream of water to the plants. Bait can be used to kill slugs and snails. Also, biological control like Bacillus thuringiensis can be used from destroying a variety of pests.
How to Get Rid Of Cauliflower Worms/Caterpillars?
Diseases and infections in cauliflower plants are not only restricted to formation of holes but there are various other complications that occur. These are caused by a variety of other animals including worms or caterpillars.
Now, we shall talk about ways to get rid of caterpillars and worms, destroying plants.
#1 Manual removal
If you can comfortably remove worms or caterpillars from plants with hand then this is a great option for you. It is quick, easy and effective to completely get rid of pests. This will stop them from damaging your plants. Also, removing pests like this will cause no harm to plants. Check the underside of leaves properly.
Check your plants routinely after handpicking worms or caterpillars. There might be some left in the process or there could be small larvae that came out of eggs that you did not remove from plants. Make sure to remove eggs as well as any worms left.
#2 Floating Row Covers
This is probably the best way of protecting your plant. It hinders access of worms to the plants. So, there will not be any damage to the plant at all.
Some row covers are used to block insects from reaching plants while there are others that are used for frost-protection or shade. You can easily pull the row covers back whenever you need to.
#3 Beneficial Insects
There are some insects that are parasitic to worms and caterpillars. Parasitic wasps lay eggs on top of arthropods like caterpillars and their pupae. So, these can be used to destroy caterpillars. When eggs hatch, they feed on caterpillars and kill them eventually.
#4 Neem Oil Spray
Neem oil is plant based oil that is extracted from seeds of neem tree. Neem is effective in controlling aphids, thrips, white flies, mealybugs and spider mites. This oil when applied coats insects and kills them.
Neem oil can be used to get rid of cabbage worms when combined with other appropriate methods. It does not kill pests but can help in reducing severity of damage.
#5 Bacillus Thuringiensis spray
Bacillus thuringiensis is a naturally occurring, soil dwelling bacteria. It is widely used in biological pesticides. It is commonly used to control cabbage worms and cabbage loopers.
It is best to use Bt spray in evening hours. It is because spray can degenerate rapidly in sunlight and washes off with rain or water. Do not over spray plants.
#6 Polyculture or Companion Planting
Polyculture refers to planting a variety of different plants together in one space. It will increase biodiversity in your garden. Prefer companion planting with pest-prone crops. For example, companion plants for brassica are tyme, oregano, dill, onions ,garlic, lavender and marigolds.
These plants can also do the work of trapping and are thus called ‘trap crops’. They may attract cabbage worms towards them leaving your precious cauliflowers alone. Then, all of the lured caterpillars or cabbage worms can be handpicked away.
There are various pests that can cause holes in the cauliflower leaves. Infection from pests does not mean that plants cannot be saved or there is no solution or option left.
You can still save your cauliflower plants using above methods. Take care of plants consistently to avoid occurrence of any infections due to pests.