When we start thinking about our gardens, great green bushes are pictured, along with healthy harvested onions, and beautiful bushy herbs. In this article, we will take a look at what an aphid is, aphids in potatoes, what to look for and how to avoid or manage them.
What we don’t always think about is the yellow we start to find on our tomato leaves, holes in the apples or the infamous little brown and black spots on our potato leaves.
Each different plant seems to have its own personal pest problem.
However, there are some pests that have a highly varied diet and will eat just about everything in sight.
One of these such terrors is the aphid, which belongs to a very large family, a superfamily, of pests called Aphidoidea.
There are many different insects within this family, but together they do incredible amounts of damage to vegetables and ornamental plants of all kinds.
Some of their preferred snacks include things like squash, cucumber, beans, lettuce, beets, chard and potatoes.
If you would like more information about growing your own potatoes, please read my article about growing your own potatoes. This covers everything you need to know from planting, preparing seed, growing, harvesting and storage and more about this great vegetable.
What is an aphid
An aphid is a small bug, about 1/8 of an inch long (~3 mm), or the size of a pinhead.
They can also be called plant louse, greenfly, black fly, or ant cow because of their colour and feeding habits.
They feed on the sugary juice, or sap, that is held inside of the leaves, stems and roots of a plant, willing to attack every bit.
Obviously, the fact that they take the sap out of a plant, like bleeding it dry, is enough to want to keep them out of the garden.
However, they also are known for spreading diseases from one already diseased plant to a different, healthy one.
They can do this because of the tube-like projections from their abdomens that they use to feed.
Where do aphids come from
Aphids are also incredibly productive since a female aphid will give birth to living young during the summer season.
Then, at the end of the season, the females will produce eggs that survive through the winter and are the new crop of aphids in the coming season.
Aphids only grow wings once they become adults and begin to struggle with overcrowding on their host plant, something to watch out for.
Types of aphids
There are 4,000 species of aphids, and growing, that have been discovered and described and about 250 of these are major pests to crops and flowering plants.
Although aphids are plentiful, each species generally has a family or group of plants that it likes to eat.
There are specific aphids that eat apples, one of which includes Aphis pomi, for cabbage plants Brevicoryne brassicae, and for grains Toxoptera graminum.
Aphids in potatoes
Here, though we are mostly going to focus on those that bother the potato plant, mainly what is known as the potato aphid, Macrosiphum euphorbiae.
This aphid’s life cycle begins with rose plants, which host the eggs during the winter.
They then hatch into pink and green young “baby” aphids and begin to feed on the rosebuds and leaves, but in early spring, migrate to potatoes and stay on them as their summer host.
A new generation of potato aphids will come into play about every two to three weeks and are most known for being the carrier of tomato and potato mosaic virus diseases.
Symptoms of aphids
An aphid will always leave behind some obvious symptoms and are generally fairly easy to spot and identify themselves.
Every area that they feed on will end up resulting in a blackened spot on the leaf, first yellowing and quickly turning into a dead spot.
If there are a large number of aphids, then the entire plant will start to wilt.
In potatoes, they often cause the potato leaves to roll up as the sap is sucked out from the inside.
Honeydew from aphids
Another thing to watch out for is “guardian” ants.
Ants commonly act as a sort of shepherd to aphids as they like to feed on the excretion from an aphid, called honeydew.
As aphids continue to eat, they leave this sticky, shiny substance behind and the ants will collect it.
Honeydew is also a host for the black sooty mould fungus, looking exactly like it is called, and can be found growing in it.
If there is not a large number of aphids already present, then another symptom to look for is deformed new leaves, flowers or stems.
Management of aphids
The first thing I always start with when trying to get rid of an aphid problem is simply to spray the infected plants down with cold water.
They can’t hold on very well and will generally not be able to find their way back to the same plant, this works well if it is only one plant you need to care for.
Another way to manage small populations is to dust them with flour as this will cause constipation and quickly kill them.
If the aphid population has already gotten out of hand, then using a horticultural oil, like Neem oil, will help to get rid of them.
To use these, follow the instructions on the package so that the concentration or application doesn’t end up damaging the plant itself.
One more method is to mix together water, about one quart, a teaspoon of liquid dish soap and just a bit of cayenne and spray this on all the infected plants.
There are many sprays which will take care of aphids – just call with your local crop advisor.
All in all, even though aphids can wreak havoc, there are many ways to get rid of them and keep potato crops safe.