Garlic Troubleshooting Guide

Garlic is pretty tough.

That doesn’t mean that you aren’t going to run into some problems. Garlic is prone to several different diseases and pests. Most of these problems come directly from the soil so it is important that you rotate your crop every year.

Here are some of the most common problems you may run into with your garlic crop and what you might do about them.

Overwatering can cause rot. If you notice your plant yellowing or dying back, check a few of them and check the water content of the soil. If you see that rot is beginning to form, cut back on the watering.

Bulb mites will often grow under the roots of the bulb and can result in stunted garlic plants. They are white, shiny and fat. They can be very tough so they best way to deal with them is by rotating your garlic plantings.

The pea leafminer won’t cause you too many problems. They show up initially as tiny eggs laid within the leaf tissue. When they hatch, the larvae tunnel inside the leaves. When they mature, they leave the plant as tiny black and yellow flies. The tunneling done by the larvae is really no big deal to your garlic plant but you still want to be careful because these guys can pose a serious threat to other leafy plants nearby.

The wheat curl mite is another one that, while making your plant look pretty rough, doesn’t pose a serious threat. You’ll know you have it if the garlic leaves are streaked and twisted and overall growth stunted. The wheat curl mite can cause problems at harvest. Your cloves will dry out and crumble if its in there. This is another one that can be dealt with through a hot water treatment just before planting.

Basal Rot is a slow developing fungus, typical of warmer climates, that often causes the leaves of the plant to die back. Often times, symptoms of the rot are not even evident until post-harvest when you may note a white fungus at the bottom of the bulb. Keep an eye out for this once your garlic is hanging in storage.

White Rot, more typical of cooler climes, looks a lot like basal rot but white rot often tends to simply kill the garlic plant outright. This is a tricky one because while you can reduce the chance of white rot by dipping your seed clove in hot water right before planting, too high a temperature can kill your seed clove.

Downy Mildew looks like a whitish, furry growth on the leaves. They may also yellow. Young plants may die while older ones will see stunted growth. If you suspect downy mildew, check the garlic you’ve stored. It will be shriveled, have a blackened neck and might feel moist to the touch. Downy mildew can survive for years in the soil. It loves to be wet and is often transported by moving water so go for wide-spacing of your rows, good air circulation and avoid over watering.

Botrytis Rot, also known as “neckrot” will hit the stems with a gray fuzz. The stems will also fill with water. Typically, “neckrot” will hit your bulbs and/or plants in warm, wet weather so be sure to get your bulbs rapidly dried out before storage and make sure they get a lot of air circulation. Cooler storage temperatures may also help. In the garden, be sure to use disease free bulbs and again, space your rows and get lots of air between the plants.

Penicillium Decay looks like blue-green mass on your cloves. It will dramatically reduce the growth of your plants. Be sure your bulbs are properly dried before storage. When planting, take care to put the clove in immediately after it is ‘cracked’.

Nematodes show up in a multitude of ways. Common symptoms include erratic plant stand in the field, stunted plants, yellowing, deformed bulbs, and stem swelling. You’ll actually have to get your field tested by a lab if you want to find out about these little buggers. If you have them, you’ll want to rotate your plants away from them…if possible. They can move around quite a bit. A traditional way of dealing with them is giving the cloves a hot water soak right before planting.

You may find that you have other issues. Some genetic abnormalities can resemble disease symptoms. You might see a great variety of colors in the leaf of your plant. This is actually quite common and results in reduced photosynthesis or bulb deformation. Another common genetic problem may result in a breakdown of the outer cloves of garlic where sunken tissue will turn a dark yellow color.

Finally, the clove turns very soft, clear and sticky. There is not much you can do about this except to remove the problem cloves from your collection. Don’t plant them again!