Aphids live on some lemon trees for food. They suck plant sap directly from citrus tree leaves. These small pear-shaped bugs aren’t as common on lemon trees as on other species, but they can still kill a young tree.
You can eliminate aphids on lemon trees by spraying the trees with water to wash the bugs or with pesticides. Aphids can be prevented by using soap and water sprays or by planting petunias and borage.
Aphids that eat lemon trees don’t need to mate to lay eggs. This means they can lay at least tens of eggs at a time and repeat the process easier. The final result is an invasion that can kill a lemon tree.
Do aphids eat lemon trees?
Aphids only eat young lemon tree leaves. They stay away from old lemon trees which don’t have as much leaf spa and which are harder to pierce with their sharp mouthparts.
If your lemon tree is young you need to take precautions to keep these bugs away. Chances are aphids won’t appear on your old lemon tree. This preference for young leaves is seen in aphids that attack other types of plants and vegetables as well. It means you need to take precautions when planting the lemon tree as aphids seek out young trees to feed on.
Which aphids eat lemon trees?
Aphids prefer other types of trees and vegetables to lemon trees. However, species such as the Brown citrus aphid are known to exclusively feed on a lemon.
Identified by either a brown or a black body, these aphids aren’t easy to spot as they grow to half an inch. It might already be late when you spot these aphids on your lemon tree as you can be facing a small invasion.
Up to 40 generations of aphids can feed on lemon trees per year. This means the tiny sap-sucking bugs can stunt tree growth or even kill it.
When can you be sure your lemon tree suffers from aphids?
You need to know what counts as an actual aphid on a lemon tree before proceeding to eliminate the bug or take preventive measures against it.
When you see honeydew on the leaves – this is a sticky substance aphids leave whenever they eat leaves. The substance attracts plenty of ants.
When leaves turn brown – brown leaves are dead leaves impacted either by diseases or by a bug such as aphids.
When lemon tree leaves turn yellow-green lemon tree leaves first turn yellow before turning brown when affected by aphids.
When lemon tree leaves change their shape – tree leaves that curl up or that lose their natural vigor might be affected by aphids.
8 methods to get rid of aphids on lemon trees
Killing aphids and preventing them on lemon trees require different measures. However, you can consider both elimination and preventive methods if you have aphids on your lemon tree and plan to eliminate them and keep them away for good.
1. Spray lemon trees with water
The most natural or non-invasive method of eliminating aphids from your lemon tree is to spray it down with water. You can use a long gardening hose to wash away all aphids and other bugs they might attract to the tree.
Caterpillars are among the most common species on lemon trees together with aphids. Some ants might also follow the honeydew or black soot mold aphids might bring on a given tree.
Pure cold water is better and safer for your lemon tree. You should not use warm water or hot water to kill the bugs as this can damage the tree.
2. Spray lemon trees with soap and water
Soap and water are a good preventive combination once aphids have been removed from the tree. Liquid soap or dishwasher soap and water are a good mix when it comes to coating your lemon tree in the spring and at least once more in the summer with a protective barrier.
Lemon trees might show different types of reactions to harsh soaps so it’s best to use only natural ingredients soaps. A gallon of water can be mixed with 1 cup of soap for an effective barrier which lasts 1-2 months.
3. Spray garlic or vinegar
Many people only use natural pest repellents on lemon trees. Among all of the natural solutions, garlic is the one with a reduced impact or no impact at all on the leaves of your young lemon tree.
Up to a few pieces of garlic can be mixed and infused overnight in a gallon of water before spraying on the lemon tree. You need to re-apply a mix of garlic and water every month or soon after heavy rain if your lemon tree is outside.
A mix of water and vinegar is another very good natural alternative that deters but doesn’t kill aphids when sprayed on lemon trees. A cup of vinegar is mixed with a bucket of water and then sprayed all over the leaves and the tree bark. Even the soil around the lemon tree is coated in vinegar for a superior protective barrier.
4. Attract ladybugs
Some ladybugs such as numerous gray and white ladybug species eat aphids. You can consider attracting these ladybugs to your garden to keep aphid populations low.
You can attract ladybugs by planting flowers around the lemon tree. These bugs might initially be attracted to colorful flowers but they soon eat all aphids they find nearby.
5. Spray lemon trees with jojoba oil
Jojoba oil is a type of essential oil known to deter aphids. You can apply a few drops of essential oil to a sprayer and coat the young small lemon tree properly to keep aphids away or even to kill them if sprayed directly.
Jojoba essential oil is different from other essential oils on aphids as it works. Not all essential oils are efficient against aphids. Furthermore, since essential oils aren’t always affordable, this method is mainly recommended for small potted lemon trees which don’t need as much spraying as mature trees.
6. Consider pesticides
Pesticides are very efficient at killing aphids on lemon trees. You can use various types of pesticides but horticultural oil sprays tend to do the job well.
Pesticide application is mandatory when it comes to a serious invasion you notice late. It’s recommended to use pesticides on lemon trees when more than 25% of their leaves are affected (in color or shape) by aphids.
Pesticides also have the most potent protective role in keeping aphids away after they are killed. Make sure not to spray lemons themselves as they can absorb pesticides. You also need to wash lemons before eating them if you use pesticides on the lemon tree.
7. Spray alcohol
Spraying alcohol on the leaves of lemon trees can protect them from aphids and all types of other bugs and insects. Pacing is key when it comes to spraying alcohol as you can use it in strict conditions as a natural pesticide.
Alcohol should not get to the roots of the lemon tree as it can be detrimental. You should only spray the top and bottom parts of the leaves with alcohol to keep aphids away.
Spraying frequency differs as it’s mostly influenced by the tree watering frequency. You should spray the lemon tree with a mixture of water and alcohol after heavy rain.
8. Plant citrus aphid-deterring plants
Some flowers act as natural deterrents for aphids on lemon trees. The key is to plant these flowers around the lemon tree so that they create a barrier against bugs. You can choose between the following types of aphid-deterrent flowers as other types may even attract the bugs.
Petunias are small colorful flowers that aphids hate. You can plant them in the ground around lemon trees or in pots around lemon trees. Some petunias might even be planted in hanging baskets.
Multiflora petunias are the easiest to care for.
Trailing petunias might also be a good option as these flowers spread rapidly creating a larger barrier against aphids.
Borage flowers are also grown against aphids. These small bristle-full blue flowers are known to deter these bugs. You need to plant borage in full sun, just like the lemon tree for it to grow vigorously.
Can aphids kill lemon trees?
Aphids can damage young lemon trees as they have a reduced impact on mature lemon trees. They tend to damage the leaves of young lemon trees as they are easy for them to pierce for sap. Aphids can also damage the roots of lemon trees in their larval stage.
Do aphids spread disease on lemon trees?
Aphids make honeydew which can favor the growth of sooty mold. This is a type of black fungus that covers plant leaves and stems essentially reducing their natural capacity for photosynthesis. Also known as black mold, sooty mold needs to be washed or removed by hand from the leaves of lemon trees after killing the aphids that caused it.