Garlic is a bulbous plant that packs a robust aroma and flavor that many of us cannot do without. The best part about garlic is that it is a fairly easy crop to grow, and for the most part, is pest resistant. That said, this plant does not lack its share of onion and garlic diseases and pest infestations. Worms in garlic mostly cause poor garlic harvest.
Common Onion and Garlic Diseases and Pests
Many types of worms and diseases can affect poorly managed garlic fields. These pests and diseases can damage garlic bulbs, leaves, and the roots of your plants. This damage impacts the yield and quality of garlic harvests. As such, farmers must be able to identify these pests in order to curate a potent pest management plan.
This article will take you through some of the most common garlic bugs and worms that affect garlic crops, how to distinguish them, and the best management practices to avoid these worms.
Onion maggots are the larval form of the onion fly. These worms are most destructive in their larvae form. They use their hooked mouth to enter bulbs and cause large cavities. The onion fly reproduces inside garlic plants.
Once it chooses a host, it lays groups of elongated white eggs on the leaf surface, shoots, and even roots of the host plant. The eggs hatch within 3-8 days and feed vigorously on the developing shoot and young roots of a growing garlic seed for 20 days before entering the next phase of their life cycle.
Onion maggots are more restricted to cooler coastal climates and the intermountain region. However, these pests can cause onion growers to lose more than half of their yields without proper planning and insect control measures.
Effects of Onion Maggots of Garlic
- Rotting of garlic bulbs
- Yellowing of leaves
- Reduction in bulb development
- Damage and death of seedlings.
Treating Garlic Seed Cloves With Onion Maggots
Prevention is key to avoiding damage from onion maggots. For starters, wait to plant later in the spring after the first generation of adult flies has emerged. This will avoid the first generation of egg-laying by adult flies that overwintered in the soil during the previous years. Other preventative measures include:
- Avoid planting onion or garlic immediately after allium crops. Instead, opt for efficient crop rotation. This will give affected soil enough time to be free of the pests.
- Clear out all plant debris of previous cultivations: Soil tilling destroys larvae by leaving them visible to predators.
- Leave considerable space between plants during planting
- Only plant disease-free seed
- Observe your garlic crops and keep removing affected plants.
- Increase maggot predators like the rove beetle, spiders, ground beetle by providing sufficient mulch to attract them
Onion thrips are the garlic plant’s most common pests that attack garlic plants and the members of the allium strain of vegetables. They are small insects that range from 1 to 1.3 mm. in size. These pests suck the sap from plants, gradually slowing growth and bulb production.
The entire garlic field can wilt and die if the infestation is severe. Other than being capable of extensive damage to growing garlic plants, onion thrips also act as a transmitter for the spread of disease.
Effects of Onion Thrips on Your Garlic Plants
Onion thrips usually cause severe harm to garlic plants. Once they attach to garlic leaves, thrips use their mouth to pierce and rip leaves. They then suck up the sap discharged from these injuries, leaving your leaves with white or silverish patches. As a result of this damage, your entire crop may suffer:
- Dehydration: These injuries allow excessive transpiration of water causing your plants to dry up from dehydration
- Poor photosynthesis: Thrips damage the green leaf area affecting photosynthesis
- The damaged areas allow the pathogens to enter the plant, stunting its growth
How to Control Onion Thrips
Some effective ways to prevent or manage an onion thrip infestation include:
- Plant garlic variants that are thrip tolerant or resistant
- Avoid planting successive garlic crops or other onion thrip host plants like cabbage, cotton, melon, pumpkins, onions, etc.
- Treating garlic seed cloves before planting with hot water before planting is an effective way of reducing onion thrips infestations.
- Avoid surface irrigation systems. Instead, use sprinkler systems
- Practice proper field sanitation by getting rid of old plant remnants and produce.
- Use heavy mulch to deter thrip infestations.
Dry Bulb Mites
The dry bulb mite is also known as Eriophyid mite, a common garlic pest that causes irreversible impairment to garlic crops. Off white in color, shiny and globular, adult mites can grow up to 0.25mm in size. These pests can be found huddled together under the root plate of garlic cloves or onion bulbs.
Dry bulb mites are an extremely dangerous pest since they can be spread through the air thanks to their low body mass. Unfortunately, if you do not know what you are looking for, a bulb mite problem can go unnoticed. These mites are usually not seen on the bulb but feed mainly on the roots and basal plate. Once they attack, these mites slow plant vigor, reduce stands, and increase the risk of diseases post-harvest.
As a result, they reduce harvest drastically and generally stunt plant growth. Since this pest can overwinter and live from one growing season to the next, it is recommended that you rotate planting by skipping the allium varieties in successive years.
These mites are also troublesome in storage. In storage, mites move into the garlic bulb. As they feed, they create wounds that provide an entryway for bacteria and infectious fungi such as Penicillium and Fusarium.
Effects of Dry Bulb Mites on Your Garlic Plants
Bulb mites reside between garlic cloves and sprouting leaves. Galls are a sign of their presence. Galls grow on leaves and can be likened to tumors or worst in animals. Most of the time, dry bulb mite infestations are so small and incognito that they often go unobserved and untreated. However, once they attack, you may notice:
- Yellowing of leaves
- Stunted leaf growth from bulbs. the leaves may appear twisted or curled.
- Stunted bulb development may also be noted. most bulbs lose their firmness.
- The cloves may look shriveled.
How to Prevent or Manage a Dry Bulb Mite Infestation
Dry bulb mites survive in the soil feeding on the leftover organic matter from the previous crops. As such, it is recommended that you allow the foliage from the previous crop to break down completely before any new crop, especially garlic or onion, is planted again. Other bulb mite management options include:
- Hot water treatment of garlic seeds: This preventive measure is effective but may decrease germination.
- Flood irrigation is another effective way to reduce the number of mites in the soil.
- Soak cloves for 24 hours in 2% liquid dish soap and 2% mineral oil before planting.
- Dust garlic bulbs with sulfur
- Avoid successive cultivation of garlic and onion plants.
- Plant cloves as opposed to bulbs as they may be infested with dry mites, especially if they’ve been in storage for a long time.
- Treat your garlic seed cloves before planting can effectively prevent infestation.
- Plant after heavy rain or flood irrigating your bed to limit the number of bulb mites in the soil.
Garlic bulbs infected with bulb mites may rot and fail to produce new growth. As a result, it may be off-color, stunted, or distorted if they produce new growth. Once inside a bulb, bulb mites rapidly turn the bulb into rotten pulp.
Also known as eelworms or roundworms, garlic nematodes are microscopic worms that live in the soil or plant tissue. These worms grow up to 1.5 mm long. Large numbers of nematodes can destroy an entire plot of healthy garlic plants from the leaves all the way to the roots.
Nematode bites can result in the deformation and the discoloration of the bulb. The worst part about garlic nematodes is that they expand in population for years with little to no signs of damage, only for them to decimate your entire crop in a short period.
Effects of Nematodes on Your Garlic Plants
Nematodes can stunt growth in garlic plants. Once they attack, they cause the stems of garlic plants to become swollen. As a result, you garlic plant :
- Leaves lose their green color: the leaves turn pale yellow, wilt, and collapse
- Stunted growth: Nematodes feed on cell sap, causing distress and putting garlic crops in danger of dying back prematurely.
- Garlic bulbs turn brown, shrivel and become lightweight
- Wrapper layers often crack and become detached from the basal plate of the bulb
How to Control Garlic Nematode
- Proper field sanitation is vital.
- Crop rotation plans of about 3 years are ideal. This allows for the starving of the nematodes during this period.
- Disinfect garlic bulbs by soaking them in a formalin and water solution
- Fumigate field before planting garlic or any other possible host plants
- Do not plant garlic bulbs infected by nematodes
- Areas with cool temperatures and low humidity levels provide unfavorable conditions for the reproduction and growth of nematodes.
The Leek moth is a dangerous pest that destroys a garlic crop and poses a threat to biodiversity. The larvae of the leek moth cause extensive damage by tunneling mines and feeding on both the leaf tissue and the growing bulbs.
How Does the Leek Moth Affect Garlic Growth?
The larvae of the leek moth feed on leaf tissue and occasionally on garlic bulbs. Once it attacks your garlic crop, you will notice a tunneling mine pattern. Left alone, this pest can cause extensive leaf damage, sometimes leading to the death of the plant.
How to Control Leek Moth
- Use pheromone traps
- Trap crops attract leek moths. These pests lay their eggs on the trap crop and not on your garlic.
- Remove and destroy all old plant debris
- Practice proper plant rotation
White rot is one of the most catastrophic garlic diseases caused by a fungus. Once it attacks, it can wipe out entire fields of garlic plants. Unfortunately, it also produces sclerotia, which remains viable in the soil for decades. When a white rot breakout is low, the infected plants may cull, but a complete restart in a different location and sterilized tools is a must when widespread.
White rot can be hard to differentiate from other diseases mentioned above. it usually affects patches of plants rather than individuals. Growers may also note stunted plant growth, followed by early yellowing and eventually death of the foliage. If allowed to progress, you may notice rotting of the stem above the bulb.
Effects of White Rot on Garlic
- The leaves may start to yellow, wilt, and dieback
- leaf and root decay will start
- Growth will become stunted
How to Manage White Rot
- Practice strict sanitation
- Crop rotation
- Seek out guaranteed clean garlic seed
- Use disease-free planting material
Wireworm is the larvae form of the click beetle. These worms can live in the soil for up to 6 years before transforming into a beetle. These worms are phytophagous, meaning they feed on plants such as garlic but are also carnivorous.
Effects of Wireworms on Garlic Plants
Extensive root damage from wireworms can cause a crop to wilt or stunt its growth. Usually, these worms eat into the outer layers of a garlic bulb. The mark they leave, however, is not contagious. It can be removed by peeling the affected layers off.
Cloves affected by wireworms can be used as seed garlic unless the flesh has suffered damage been compromised, allowing other diseases like fungi to infect the clove.
How to Manage Wireworms
Although farmers rarely experience serious wireworm infestations to see any significant damage to their crops, if things get out of hand with your case, here are some basic practices to recent a wireworm infestation in the soil.
- Cover crops: Cover crops like Brown mustard produce a bio-fumigant that dissuades wireworms and may even kill them. Buckwheat is another great cover crop that pushes populations of wireworms down in the soil. Cover crops also help prevent female wireworms from laying eggs near or around the plants.
- Trap crops: This option is ideal when there is a small number of wireworms are present in your garden. Plant your preferred trap crop between garlic beds to deter them from your garlic. Plant the seeds close together in a straight line. Radish, wheat, and even potatoes make great wireworm traps. Once mature, harvest the entire clop, including the wireworms.
Wheat Curl Mites
Wheat curl mite is a cigar-shaped pest with two pairs of legs near the head. This pest affects the vigor and growth of garlic plants. Although common in wheat, this pest can also affect garlic plants.
Effects of Wheat Curl Mites on a Garlic Field
A severe wheat curl mite infestation can cause twisted, stunted leaf growth, but its major impact is upon the bulb. These mites can cause cloves to dry out. The wheat curl mite also acts as a vector for Yellow Streak Virus. Wheat curl mites are so tiny they are almost invisible to the naked eye.
How to Manage Curl Mites
There are several preventative measures you can take to prevent the onset of curls mites:
- Planting only healthy cloves: One of the most effective preventative measures is ensuring your seed garlic comes from a reputable source. Avoid using garlic from the grocery store as it may be a carrier of disease without showing any symptoms. Other good prevention practices include:
- Cull diseased plants: Do this as soon as symptoms appear. Make sure to collect all refuse, throw it into the garbage, or better yet, burn it.
- Practice cover cropping: Wisely choose cover crops to plant in your garlic plant field. Mustard, for instance, is an excellent natural biofumigant that’s been proven effective against nematodes. It also helps to build soil organic matter.
- Hot water treatment: Treating curl the mites is possible by dipping the seed garlic in hot water prior to planting.
People Also Ask
What Are the Little Worms in My Garlic?
It’s possible that the small worms in your garlic are wireworms, which are the larval stage of click beetles. When there are a lot of wireworms, they can cause significant damage to garlic plants and bulbs.
Can You Eat Garlic With Nematodes?
Eating garlic that has nematodes is not recommended. Nematodes can cause diseases in humans and animals, so consuming garlic with them can increase the risk of contracting an infection. It’s better to throw away any garlic that has been affected by nematodes.
What Does Diseased Garlic Look Like?
If your garlic is diseased, it may appear discolored and have fungal infections. The skin may have spots or streaks and the cloves could be misshapen or feel soft when touched. To avoid spreading the infection, it’s important to promptly remove any garlic showing abnormal signs in your crop.
What Are Common Garlic Diseases?
There are several diseases that can affect garlic, including white rot, leaf blight, stem and bulb nematode, rusts, and common scab. If left untreated, these diseases can cause significant harm to your plants. Therefore, it’s essential to keep a close eye on your garlic crop and promptly address any signs of disease.
In conclusion, prevention is a useful stopgap tactic for garlic growers. While most of these pests can be dealt with by applying commercially available pesticides, the results arent always consistent. Also, these pesticides may kill beneficial insects that are better than garlic worm killers. Thus, the most effective control is to practice preventative measures.