Garden Like a Boss

Aphids 101: Methods to Outsmart the Little Vampires

By James Loomis

Few things crash the garden party harder than the arrival of aphids. In an instant, visions of effortless harvest and flawless plants come to an abrupt halt. One of the first pests a beginner gardener learns to identify, it’s really hard to miss them once they show up. And show up they do! One day the plants are spotless, the next leaves are curling under writhing masses of plump little aphids.

When it comes to common garden insect pests there are none more ubiquitous, consistent, or fascinating than aphids. Travel to the other side of the globe and, if there are plants, you’ll find aphids ready to dip their filthy little mouth straws into tender plant tissues. So how is it these minuscule plant vampires wreak so much havoc? And how do we effectively combat them?

To formulate an effective strategy we need to understand the biology of the aphid. They feed primarily on sap by tapping into the plant’s vascular structure. Once they puncture the plant tissue, these plump little sugary sweet beings of pure evil begin sucking on the high-pressured fluid. I’m pretty sure they also feed on anguish as a gardener’s favorite plants are lost, and acquire yet more nutrients from a their frustration and tears.

The devastating power of the aphid comes from its ability to reproduce rapidly. Wrap your head around this one: Aphids can give birth to pregnant young. Seriously. Back up and read that again. Aphids can give birth to pregnant young. It’s an ability called parthenogenesis, asexual reproduction that results in nymphs that are clones of their mother. In one season, a single female can produce literally thousands of aphids who each mature rapidly and do the same. They can do this for upwards of 40 generations before needing to reproduce sexually.

With sexual reproduction, the new generation has the capacity to lay eggs and fly, so when conditions become crowded, aphids just produce a new generation with wings, who fly off, find new territory, mate and start all over again.

Aphids thrive in cooler weather. Preemptive action now can prevent an aphid plague in fall.

Defense #1 Beneficial insect habitat

A lush garden flush with predatory insects sees very little sustained damage from pests. Fortunately for the gardener, aphids secrete a sticky, sugary liquid called honeydew that predator insects find delicious. Plump, slow and tender skinned with no defenses, they are the favorite snack of many beneficial insect predators who love to pierce and drain them dry (my nickname for aphids is “ladybug juice boxes”). Bear in mind that most beneficial insects survive on nectar most of the time and only gorge on aphids when outbreaks occur. Create a garden habitat to sustain aphid predators throughout the season by devoting 20% of your space to perennial and annual flowers. (For more info on creating beneficial insect habitat, see CATALYST, April 2016.)

Defense #2 Avoid insecticides

This includes even organic insecticides, which still kill non-target insects—lacewings, ladybugs, parasitic wasps. And, trust me, you have a way higher chance of killing all the good bugs than killing all of the bad bugs. Products like neem oil are completely ineffective against aphids since aphids are not consuming plant tissue.

By avoiding wholesale slaughter of insect populations, we allow the numbers of our beneficial insects to build up to control levels. Rock the boat with pesticides, and it’s back to square one. This is a long-term solution. Quick fixes are temporary, but balance will be achieved.

Defense #3 Healthy plants defend themselves

Pests and disease are nature’s way of removing plants that are weak, so make sure your plants are healthy and planted in the right season. Are they getting too little or too much sun? How about water? If a transplant, was it planted at the right time and healthy to begin with?

The number one spot that aphids show up is on brassicas, especially kale, because they are cool weather crops they immediately become disadvantaged with increasing heat. Likewise peppers are hard hit as fall sets in and temperatures cool down.

Offense 1: Blast ‘em

When done on a regular basis, there is nothing more effective for dislodging aphids than a strong blast of water from a hose nozzle (I prefer the “flat” setting). Pay particular attention to the underside of leaves. Remember, aphids feed by inserting their mouth parts into the plant tissue so as you knock them off the plant you are literally tearing part of their face off. Makes you feel a little better, eh? Even if you see them crawling around on the soil, they won’t last for long. This technique is most effective when done regularly, every two or three days.

Offense 2: Soap ‘em

Make sure you have real liquid soap, not a detergent (most kitchen products are actually detergents). My favorite for this task is good old Dr. Bronner’s baby soap (it doesn’t have scents or other oils added). Add 1 teaspoon of soap to 1 quart of water, put in a spray bottle and spray the aphids. I like to do this in conjunction with Offense 1, and will alternate the days I do each until the aphids are under control. DON’T use soap on your plants during the part of the day with intense sun as it can burn the shit out of the plant foliage. Always test out your soap solution on a small portion of a plant first, and check it the following day.

Offense 3: Get rid of ants

Aphids are the cattle of ant ranching operations. Ants herd, protect, and care for aphids in order to have access to the sweet honeydew they secrete. I’ve watched a guard perimeter of ants defend colonies of aphids against ladybug larvae intent on consuming them. Ants will even take aphids underground in late fall into their burrows, then bring them back up in the spring for another season of ant ranching. Needless to say, if you have this symbiotic relationship occurring in your garden, you aren’t getting rid of the aphids until you get rid of the ants. Unfortunately, getting rid of ants organically is outside of the scope of this article. Stay tuned for a future edition.

Remember, gardening is the most successful when done as a regular practice. It isn’t a chore, it’s an opportunity for connection with the natural world. Being fully present in your garden, walking through it daily, and deeply observing the ecosystem you steward leads to not only the healthiest garden, but also the healthiest gardener. Make this practice a staple of your daily routine, and aphids or other pests don’t stand a chance.

James Loomis is a professional grower and consultant, and teaches monthly workshops on a variety of topics related to regenerative agriculture and urban homesteading.

This article was originally published on July 1, 2016.