Pest & Disease: What’s Eating my Potatoes?

This week’s blog has been inspired by the many questions I have had on pests and disease on potatoes.

There are a fair few things that can affect potatoes and their leaves. Let’s look at some of them here.

What is causing the holes in my potato leaves?

Small Holes

Adult flea beetles can feed on the potato plant leaves and stems and can cause small holes in the foliage. It doesn’t usually affect the plant’s productivity or growth, but could cause a problem later on in younger potato plants. This is because when their eggs are laid and then hatched, the larvae can feed on young potato tubers. The adult can lay eggs in the cracks of the soil near the base of the plant. They can overwinter under leaves or in grass. The larvae like to feed on the stems that are under the surface and on the tubers, which creates pimple-like lumps on the potatoes and when the potato is cut you can see small like tunnels.

What’s my solution?

Ways to prevent this happening can be by piling lots of mulch up around the potatoes and removing weeds and leaves from the edges of the beds. Also, make sure you rotate your potatoes every year to help prevent pest and disease build up. Remember that potatoes are a soil conditioner, so are great for breaking in new beds.

The Colorado beetle

Large Holes

Large holes in potato leaves can be caused by the Colorado beetle. These beetles lay yellow eggs on the underside of your potato leaves. When the larvae hatch they are hungry and can destroy plants very quickly, causing large holes in your potato leaves. They can easily strip a plant of its foliage and attack flowers as well.

What’s my solution?

These beetles are very hard to control however, my advice would be to inspect your plant and pick off any leaves with egg clusters underneath and scatter buckwheat seeds in between your potatoes. The buckwheat will attract beneficial insects that will deal with these bugs in a natural way. I also highly recommend companion planting your potatoes with beans to help with this problem.

The other day someone also told me of a spray they use with basil leaves. Crush a handful of basil leaves and soak in water over night. Strain and add a teaspoon of oil and spray onto the leaves. I imagine it is the volatile oil in the basil that the beetles don’t like. Give it a try and let me know how you get on!

Preventing the spread

My final tip is that, if you have used mulch around your potatoes and have experienced a pest problem and but want to use this mulch elsewhere in your garden after harvesting, my advice would be to spread it out on a tarp and look to see if you have any beetles present. Then catch and crush these beetles. You could also spray the mulch with EnSpray 99 then reapply somewhere else. However, if your mulch is infested with beetles, there will most likely be eggs there so burning is the way to go.

Happy gardening!

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