aphids on pot plants

How Can I Kill the Aphids on a Bud?

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Aphids can wreak havoc on plants when their numbers grow out of control. These small insect pests cluster on buds, shoots, leaves and stems, piercing tender parts of plants with their needle-like mouth parts and sucking out the plants’ sap. The shoots of heavily infested plants are stunted, and the leaves may turn yellow and curl up and become distorted. Many species of aphids infest plants, but the control and management methods are similar.

How to Identify Aphids on Your Plants

Before setting out to control the aphids on your plants, check that you’ve made the correct identification, or your control attempt may be ineffective. Aphids are small, soft-bodied insects that are roughly pear-shaped. Their colors vary, depending on the species, and they include green, red, black, yellow and brown. Some aphid species are covered in a waxy or woolly coating.

Most adult aphids do not have wings, but in most species, wings develop at certain stages of the life cycle to enable the insects to disperse more widely. You’re most likely to spot winged aphids in spring or fall or when the population numbers are at their highest. A body structure that’s unique to aphids that can be used to make a clear identification is a pair of tiny tube-like protrusions at the rear of the insect, called cornicles.

Aphids most often feed in groups, though you may spot single insects. You’ll see clusters of aphids on your plants, perhaps in a range of sizes due to the presence of adults along with younger insects. Some species are root aphids, which live and feed on the roots of plants. When disturbed, aphids move slowly, unlike other insect species that look similar.

Controlling Aphids Without Chemicals

When you’re growing food for your family, you may be reluctant to reach for a commercial insecticide spray when you spot aphids on your vegetables or fruit trees. Or, you may simply want to avoid introducing artificial and potentially harmful chemicals into the environment. Whatever your motivation, your choice brings benefits to your garden and the effectiveness of your aphid control.

Many insecticides are broad-spectrum, which means they destroy most insects, including beneficial species that prey on aphids. If you spray your aphid-infested plants with a broad-spectrum insecticide, you could be killing the insects that were helping to keep the aphid population under control. Consequently, as soon as the spraying stops, you see an increase in the number of aphids, and the infestation becomes worse than ever.

Rather than spraying an aphid infestation, use one or more alternative, non-chemical control methods.

  • Check your plants regularly for aphids, and blast off any small colonies with a strong jet of water from a garden hose.
  • Prune infested leaves and stems and destroy them, wiping your pruning shear blades with rubbing alcohol before and after pruning to avoid spreading the pests.
  • Remove weeds in your garden, which can harbor colonies of aphids.
  • Avoid applying too much nitrogen fertilizer to your plants – the soft, sappy growth that overfertilization fosters is attractive to aphids.
  • Seedlings are vulnerable to attack by aphids, so sow seeds in pots in a greenhouse and transplant young plants into your garden beds.
  • Remove weeds and spread a reflective, silver-colored mulch over bare soil under your plants to repel aphids. Bury the mulch edges in soil to prevent it from being blown away.
  • If you can also see ants crawling on your aphid-infested plants, wrap a band of sticky ant-deterrent around the trunk, stem or container, which prevents the ants from farming the aphids’ honeydew and protecting them from predators.
  • Wait for predator numbers to increase sufficiently or temperatures to rise to provide natural control.

Chemical Control for Aphids

Large, established plants can often tolerate aphid colonies and suffer no long-term damage, but if an infestation becomes serious and non-chemical control methods aren’t working, it may be time to turn to chemical control. Insecticidal soaps and oils are the least harmful chemical controls for aphids. They destroy the pests by coating them in a thin layer of soap or oil and preventing them from breathing, though they aren’t effective on aphids that hide within distorted or curled leaves galls. To apply an insecticidal soap or oil, follow these steps:

  1. Dilute the product according to the instructions on the product label.
  2. Test a small area of the plant and wait two or three days to check that it isn’t sensitive to the soap or oil.
  3. Spray all parts of the plant, especially the undersides of leaves.
  4. Regularly spray the plant as advised on the product label to keep the aphid population under control.
  5. Don’t spray when the temperature is higher than 90 degrees F.
  6. Don’t spray drought-stressed plants.

Chemicals in commercial products that, unfortunately, control aphid predators as well as aphids include acephate, permethrin and malathion. These chemicals possibly kill bees, too, and they aren’t safe to use on food crops. Another chemical that controls aphids is the systemic insecticide imidacloprid, which is applied to the soil around the plant and absorbed through the roots. Imidacloprid also destroys aphid predators and other beneficial insects.

When applying an insecticide to control aphids, carefully read and follow the instructions on the product label. Wear protective clothing, including long pants, closed shoes, a long-sleeved shirt, gloves and safety goggles. After applying the insecticide, store the container in a place inaccessible to children and animals.

Aphid Control in Hemp Crops

In states where growing hemp (Cannabis sativa, hardy in U.S. Department of Agriculture plant hardiness zones 8 through 11) is legal, new growers may struggle to control this pest. Hemp aphid control is similar to controlling aphids on other crop plants, though each state has its own regulations regarding the allowable chemical controls. As with all crops intended for human consumption, cultural controls should be the first resort.

A soil drench of a chemical called azadirachtin may be effective against aphids in hemp crops. This systemic insecticide, which is applied as a soil drench, is available in products such as AzaMax for aphids. Another potential solution to aphid infestations is the fungus Beauveria bassiana. High humidity levels are required for this biological control to work, so it’s most effective inside greenhouses.

Root Aphids

Root aphids as well as aphids that feed above ground can infest plants. These pests look similar to their leaf-piercing cousins, but they differ in the damage they cause. If a plant’s leaves turn yellow and wilt or circles of plants in a crop collapse, the problem could be due to root aphids. Other symptoms include a white waxy substance or mold on the plant’s roots and a short taproot that sprouts many fine root hairs.

Controlling root aphids involves growing a different crop in the same patch of groun*d* each year, planting early, encouraging strong growth with fertilization, regular watering and removing weeds. Clean spades, garden forks and other gardening equipment after using them in the affected soil, and turn over the soil at the end of the growing season to expose the aphids and eggs to birds. Avoid using soil drench insecticides, which kill aphid predators that live in the soil.

How Can I Kill the Aphids on a Bud?. Aphids that infest a leaf or flower bud cause stunted, distorted growth, but a strong jet of water usually removes them. Small, pear-shaped, sap-sucking insects, aphid numbers increase in spring and fall but reduce when natural predators eat them or the weather turns hot or cold. …

How to combat aphids on marijuana plants

What are aphids?

A couple of aphids on a leave

Aphids are parasites that form a sub-family within the insect order Hemiptera. Like many other insects, they may represent a serious pest in many plant species, besides being an insect that can also carry several viruses and diseases. Easy to recognise as small insects of different colors (yellow, black or green) with a size of 1 to 3 mm. The body is ovoid, with 3 parts difficult to distinguish (head, thorax and abdomen). They may lack wings or have two pairs of small membranous and transparent wings. In the final part of the abdomen they have two small appendages that secrete repellents for their natural predators.

They are usually found on the underside of the leaves and stems, forming large colonies of tens (or hundreds) of individuals. They can develop symbiotic relationship with other insects like ants or bees. Aphids secrete a sugary substance from the anus – similar to molasses – that is used by ants, which in turn protect aphids from predators. Something similar happens with bees, hich incorporate this substance to their honey.

Aphid propagation

Aphids may need just one plant to complete their life cycle (monoecious cycle) or two different plants (dioecious cycle). They can also reproduce by laying eggs (sexual reproduction, involving females and males, which are smaller) or asexually (parthenogenesis). The reproduction cycle is curious; as several generations of aphids pass, and depending on environmental factors, there will be wide disparities in the offspring, with a very high degree of polymorphism. The metamorphosis suffered by the nymphs until reaching the adult stage is minimal, so larvae and adults keep a close resemblance except, of course, in regard with size.

Aphids are normally found on the underside of the leaves

Their breeding period is short, so they can quickly become a serious problem. Outdoors, eggs usually remain dormant during all winter and until weather conditions for hatching are optimal. However, it will continuously propagate in indoor grow rooms, which can have serious consequences if the pest is not treated on time. Aphids usually stay on the same plant that have colonised until the conditions are no longer favorable, at this time females are able to produce a winged offspring that migrate to another plant.

Symptoms and damages of an infestation of aphids

Aphids feed using a sucking mouthpart that pierces the plant tissue and sucks the sap of the plant. As we mentioned before, and besides the direct damage caused to the plant by their sucking action, we must also add the risk to get infected by a plant virus or another disease. By not tearing the plant tissue to feed, it is very difficult to see any sign of the plague, for they leave no marks as other insects do (spider mites, thrips, etc).

Aphids are also found on stems

The first symptom that we’ll observe is the actual presence of aphids on the plants, since they are easily visible to the naked eye. We can also spot how some leaves turn yellow and dry out, also the appearance of droppings (molasses) that can bring different diseases and fungi like sooty mold (Fumaginas sp.), which we can treat with copper oxychloride. Unlike other insects, aphids feed on the tender shoots of plants, which may look sticky. The presence of ants (Asus niger) can also be a symptom of aphids on the plant, as they feed on the honeydew secreted by aphids and take care of them, acting as a shepherd with his flock.

Thus, aphids (as other insects like whiteflies) may represent a threat that can ruin a crop for its ease of reproduction and displacement, besides their ability to carry and transmit diseases and viruses. Aphids like warm climates and environmental dryness, being spring-summer the period of natural reproduction. Using too much fertilizer is also believed to increase the risk of aphids.

Prevention and control of aphids

As always, we dwell on the importance of prevention to deal with the various pests that can affect our plants, especially if we use grow tents, which are usually ideal as a propagation habitat. Keeping the garden clean, pulling out weeds or decaying plant debris is a good way to start. We can try the beneficial association of plants, growing honeysuckle, lupine, foxglove, nettles, marigolds or wormwood – among many others – near plants which are sensitive to aphids such as roses, hydrangeas, tulips or the different marijuana varieties. Natural insecticides like potassium soap, neem oil or pyrethrins sprayed regularly on the plants always help to prevent infestations of insects, even fungi in some cases. If we choose to use natural predators, the parasite Aphidius Colemani (a small 3-4 mm wasp) feeds primarily on aphids.

If you already have a small population of aphids settled on your plants use natural and organic remedies (as we always recommend) better than chemical insecticides, which are often much more harmful to the environment. While aphids have many natural predators – like the aforementioned Aphidius Colemani, the Adalia Bipunctata or the Chrysopa Carnea), it is relatively difficult to control an infestation by simply using these predators; if they don’t work, try using other treatments such as spraying rotenone, nettle flour or garlic, or a home made tobacco-based insecticide (nicotine is a potent poison used in many insecticides). If the pest is found only in some tender shoots, we can remove the affected parts and continue with the usual prevention treatment for this pest.

This ant is protecting its aphids from a ladybug

In case we need to use chemicals, we must always look first for our Nature, trying to use chemicals as environmentally friendly as possible. Also, try to choose the one that is not effective against the natural predators of the pest you want to treat. In this case we will use a systemic insecticide (most systemic chemical insecticides against aphids on the market usually have Dimethoate as active ingredient), which will remain on the plant for a few weeks and poison any insect that feeds on it. From Alchimia we try to promote eco-friendly cultivation techniques, so always try to avoid using chemicals and leave them as a last, desperate measure.

As always, keep in mind that prevention is always the better option. The best way to avoid pests is following a series of simple steps that will impede their appearance, which will save you a lot of work and allow you to enjoy a healthy and natural harvest.

On this article we tell you how to identify, treat and eradicate an infestation of aphids on your plants. These sucking insects can quickly ruin your ]]>