The aphids that attack kale are known by the scientific name Brevicoryne brassicae, they feed exclusively on species of the Brassicaceae family. They are the ones that attack all types of cabbages, they have a size that varies between 2.0 to 2.5 mm in length and have a gray waxy layer that covers them. This last detail is what distinguishes them from other species of aphids. In this post we will analyze everything related to control aphid on kale. So if you want to eat your kales without aphids, stay and read until the end of the post.
A couple of weeks ago we were already talking about aphids in this blog. But on that occasion we took care of analyzing the control of this pest in a broccoli plantation. Therefore, if you want to learn more about aphids and how to get rid of them, I recommend that you read it. I leave you here the link so you can grow your broccoli quietly.
1. Life cycle of aphids
Before starting to talk about how to control the aphid attack on your cabbage, we found it interesting to analyze the life cycle of this annoying insect. It is important to know our enemy well before fighting him, don’t you think? 😉
This aphid reproduces in two ways, depending on the temperature of the environment. Under warm conditions, Brevicoryne brassicae colonies are composed solely of females and reproduction does not require mating. Only the females will be responsible for increasing the size of the colony. That is, females will produce more females.
The moment temperatures start to drop, the reproductive system changes. That is when the females begin to produce males. For this reason it is that in warm regions eggs are not produced, while in temperate regions it is normal for the eggs to coincide with the coldest times.
The females are also responsible for producing the nymphs, which remain on the adult females until they can survive on their own. The only noticeable difference between nymphs and adults is their size, with nymphs being smaller.
Therefore, and having said all this, we can differentiate three stages in an aphid:
- Egg: these only occur when the temperature is low. Usually this is the stage where they hibernate and remain in crop debris near the soil surface.
- Nymphs: they differ from adults by their small size. Depending on the temperature, the life cycle as a nymph varies. For example, at 25 ºC, its nymphal period is 6 days, but when the temperature drops to 15 ºC, this period can be extended to 12.5 days.
- Adults: adults can be male or female, they are characterized by their soft body and their sucking-biting mouthparts.
The total life cycle of the aphid varies with temperature. For high temperatures its life cycle reaches 16 days, while for low temperatures it can extend up to 50 days.
2. Aphid damage on kale
If we talk about aphid damage in general, we can always divide this analysis in two. The damages that are caused directly, and those that are caused indirectly. Let’s look at each of them below.
2.1 Direct demange
Like many other insect pests, aphids feed on plant sap. Thanks to the suction they make with their oral apparatus, they are able to extract the sap from stems and leaves.
The suction of the sap by the dense colonies of this aphid causes a slight longitudinal rolling of the leaves and shoots. Aphids are usually located on the underside of the leaves and in the insertion of the central shoots, giving them some protection against natural enemies and/or spraying with pesticides.
Another direct consequence of aphids on kale is decreased market value. The mere presence of some aphids makes the sale value of this product drop considerably, and it can be totally rejected. Nobody likes to eat aphids on their kale. 🙁
2.2 indirect damage
Aphids have the peculiarity of being a pest that generally does not come alone. These insects defecate the excess glucose they consume and this is very attractive to the ants. To such an extent that the ants are in charge of protecting and moving the aphids. Therefore, you will have to take care of two pests, aphids and ants.
But the droppings not only attract ants, they also favor the proliferation of saprophytic fungi. These fungi cover the leaves of your kale causing problems for the plant’s photosynthesis.
And you thought that aphids, ants and fungi were enough. Well no, there is something else. In the sucking process that aphids perform, they are capable of transmitting more than 20 harmful viruses to your kale. In general, winged aphids are the ones that transmit these viruses the most.
3. How to get rid of aphids on kale
We already talked about the life cycle of aphids and what damage they can cause to your kales. Without a doubt, it is time to start talking about how you can protect your plants from this harmful insect.
We will see several methods, some more effective than others, but remember that the best way to control these pests is to prevent them. To prevent an aphid attack you must control your crop on a regular basis. This will allow you to take the problem on time and not have great damage.
3.1 Manually remove aphids from kale
If you catch the attack of aphids on your kale in time, there are very simple methods that can help you fight them. When I say bring the pest in time, I mean that the number of aphids is small, since they have not yet reproduced.
The first method is to manually remove all aphids from your plant. Aphids are easy to see, so you will have no problem seeing and removing them. Squeeze them a bit to kill them. Then with a paper towel clean the leaves to remove the honeydew, this will prevent new aphids or ants from arriving.
You can try the second method if you see that the first one has not worked. Or if you see that it takes too long to carry it out. It basically consists of using pressurized water to repel aphids. Hold the shoots containing aphids in one hand and pour the water under pressure. Doing this several times they disappear.
As I mentioned at the beginning, these manual methods are only useful when the colony of aphids is small. Hence the importance of controlling the existence of aphids in your garden on a daily basis.
3.2 Use a special insecticide for aphids
Insecticides to kill aphids you can find hundreds, it is more depending on where you live the offer will change. Here I will leave you as a recommendation three insecticides that you can find in the Amazon store. But it does not mean that the one that you can buy in the nursery near home does not work.
- BioAdvanced (Control of insects, diseases and mites): it is a broad-spectrum insecticide capable of killing several types of insects (we already recommend it to kill armyworms). It is also very effective for the control of certain diseases and fungi. This will help you in the event of the presence of fungi along with the aphid attack on your kale.
- Bonide Pyrethrin: insecticide that quickly and effectively controls various types of insects such as aphids, beetles, webworms, leafhoppers, etc. Its design is intended to be used on garden plants such as kale, asparagus, beans, peppers, spinach, tomatoes. among others. others.
- Ortho (Insect, Mite and Disease): Like BioAdvanced, this insecticide not only kills insects but also controls some diseases such as fungi. This makes it a more than good insecticide for attacking aphids on plants like kale.
Whichever insecticide you choose to kill aphids, you need to be careful. Please read the instructions on the package carefully. Remember that if you use these types of products irresponsibly, you can cause serious damage to health and the environment.
3.3 Use an homemade pesticide
Just as I told you that there are many commercial insecticides to kill aphids, there are also many homemade recipes that you can use to try to control them. Here I will list a couple of them:
- Water and tobacco butts: take the remains of the cigarettes, put them in water for 24 hours, then strain the liquid and apply it by spraying it on the plants. It is very useful as a preventive, before seeing the aphids.
- Onion infusion: you must place 2 or 3 peeled onions for each liter of boiling water. Let stand for 10 days and then spray on the plant and soil. With this you will control both aphids and fungi.
- Nettle slurry: Place 100 g of nettle leaves in 1 liter of
Water. Let macerate for 12 days. Filter the infusion and then dilute it in 10 liters of water. Then apply by spraying. Not only does this help you control aphids and fungi, but it is also a very good fertilizer. - Infusion of rue and sage: For every liter of almost boiling water, add 200 g of rue and sage leaves. Then let the infusion cool, strain it and apply by spraying.
I leave you only four of the many recipes. Surely if you ask your parents or grandparents they know several more recipes. There are recipes that are made with garlic, orange peel, fruits of the paradise tree, among others.
3.4 Use neem oil
This oil is a natural product obtained from the neem plant. Its main characteristic is that it repels sucking insects. If they detect that the leaf or stem they are going to suck has oil on it, they leave.
Due to its oily nature, it cannot be diluted in water alone, an emulsifier is also needed. You can use potassium soap which is quite easy to get at any nursery. To prepare Neem oil, you must use a dose of 3 milliliters per liter of water. And to this add another 3 millimeters of potassium soap.
Once this is done, you must stir the mixture well until it is homogeneous and apply by spraying. Try not to apply if it is raining or if rain is forecast. This is because the rain will wash away much of the oil you have put on the plant.
3.5 Attract natural predators
One of the most natural and least harmful ways to kill aphids is through the enemies that these insects have in nature. These enemies can be predatory or parasitoid insects.
If there is a predator to be mentioned, without a doubt the most popular are ladybugs. It is a voracious predator of numerous pest insects, both in larval and adult stages. A good family of ladybugs can eat hundreds of aphids in one day. There are certain products that work as lures to attract ladybugs and thus call them to eat aphids.
Among the parasitoids there are several varieties of wasps such as Aphidius Colemani or Aphidius Ervi. Depending on the species, they can be more or less effective depending on the ambient temperature. Generally, at low temperatures, below 10°C, the adults of these wasps are inactive, unable to paracite.
3.6 Use homemade soap-based insecticide
Although I could have included this method in section 2.3, since it is also a home remedy, given its popularity I decided to dedicate a separate section to it.
To prepare this home remedy against aphids, we only need water and soap, preferably a natural one, but actually any soap that makes bubbles works.
We will also have to have a sprayer, either a special one for agriculture or any reused drum that performs this function after thoroughly cleaning any residue it may have.
The dose that you can use is 300 grams of soap for every 10 liters of water. You can adjust this dosage based on how effective this insecticide is at killing aphids on your kale.
Once you have the mixture correctly made, you just have to spray it on the plant and voila. The aphids will die, although you will probably have to make several applications before completely killing the plant.
4. Bonus Tips for Controlling Aphids on Kale
I didn’t want to end this review on how to get rid of aphids on kale without first giving you some additional tips. Although these tips will not help you eliminate this pest, they will be very useful to prevent an attack.
First of all, and before planting your cabbages, it is good that you plan your garden. This is to strategically place the plants and be able to take advantage of the fact that there are certain plants that, if placed together, work as repellents for certain pests. Among the plants that help repel aphids we can mention oregano, garlic, leek, sage, onion, basil.
Another important point to prevent the appearance and spread of aphids is the control of ant colonies. As we have already said, aphids and ants work together. So if you kill the ants that are near your garden you will be taking away a great help from the aphids.
The last piece of advice I can give you to prevent aphids from attacking your cabbages is to avoid over-fertilizing. This is because by fertilizing you promote rapid growth of new shoots, to which aphids will be attracted. If you can better avoid fertilization, and if you fertilize do it in several stages, do not put all the fertilizer together.
5. Is it safe to eat kale with aphids?
If you are one of those who like to use vegetables in your kitchen, you will surely find many insects (including aphids) in them. What you always do to prevent these insects from reaching your table is to wash them before cooking them. But in certain cases, eliminating 100% of the insects is difficult. Especially when it comes to insects like aphids, which are small and like to hide in any corner of your vegetables.
Faced with this situation, many wonder, is it safe to eat aphids on my kale? We will try to answer this question easily and quickly in this section.
As we have already said, it is impossible to eliminate all aphids from your vegetables. Based on this hypothesis and assuming that you eat a lot of vegetables, we can assume that throughout your life you have eaten aphids on more than one occasion, and if you are reading it is because you are still alive, right? With this we can conclude that aphids are not poisonous, and will not harm you if you eat them.
Having come to this conclusion, I do not mean that you should not wash vegetables. The idea is to make vegetable salad, not insects. In any case, if from time to time an aphid escapes and gets into your plate, don’t worry. It’s safe to eat aphids on your kale, at least you won’t die. 😉
More information:
- Identification guide Aphids and their natural enemies (spanish guide) – belchim.es
- Biological control of aphids – uvm.edu