The destructive allium leaf miner can wipe out an entire crop and is a pest of garlic, onions, shallots, chives, and leeks.
The mid-Atlantic and northeastern US regions are seeing a rapid proliferation of these invasive insects.
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The quaint Lancaster County in Pennsylvania was the scene of the first known infestation of the invasive allium leaf miner in the US in December 2015.
Since that time, this intrusive force has advanced relentlessly through Pennsylvania, Maryland, New Jersey, New York State, Massachusetts, and, as of early 2020, Connecticut.
As implied by its name, this noxious pest preys on wild and ornamental Allium species as well as high-value commercial crops like onions, garlic, leeks, chives, and shallots.
It can completely ruin an allium crop, resulting in enormous losses for both commercial and household gardeners.
Given that they don’t regularly spray their crops with synthetic insecticides, organic and home gardeners are particularly at risk from the allium, also known as the onion leaf miner.
Because onions are a significant commercial crop in the western US, growers are extremely afraid that this pest may migrate there.
This has been a major problem for onion growers, as Brian Nault, a professor of entomology at Cornell, stated in the Cornell Chronicle.
Where did my allium go?
We’ll first assist you in determining which animals are consuming your flowers or bulbs. Your problem may be caused by voles and mice burrowing underground, as opposed to squirrels and chipmunks digging out bulbs to eat. Your bulbs might endure the winter, only to be eaten by deer. Every issue has a special solution. To find the offenders, look for these indicators:
- Squirrels frequently dig bulbs out of the ground to eat, as do chipmunks, skunks, voles, raccoons, and rabbits. You should be able to detect traces of a skunk’s odor if one is around. You can also utilize chew marks and footprints to find the offender.
- Bulbs That Never Emerge: Occasionally, a bulb that you plant never actually grows. Something is attacking from below in this instance. Mice, gophers, and voles are typical bulb-eating burrowers. Moles are frequently held accountable, yet these mammals consume insects like worms and grubs. However, they will let other rodents to use their tunnels, which is why they are frequently accused. Some bulbs decay, preventing them from emerging. The issue is most likely present if the soil is damp and dense.
- Deer and rabbits can eat an entire bed of tulips in a single night. Foliage and flower buds are also consumed. Analyze the damage carefully to identify the animal that caused it. Deer typically create jagged tears in the plants they nibble on, whereas rabbits use their sharp incisors to cut stems at a neat angle.
- The dreaded groundhog: The big piles of soil they leave behind in the landscape will let you know whether you have groundhogs. These voracious eaters consume fragile shoots once they emerge from the earth as well as underground bulbs. Even if you can’t win with them, they are adorable.
What creatures consume alliums?
The high elevation plant Allium bisceptrum, often known as the twincrest onion or aspen onion, is a native of the western United States. It grows as a perennial in California, Arizona, New Mexico, Nevada, Oregon, Washington, Idaho, and Utah, where it prefers moist, shady environments or wide meadows. [4]
Because the leaves of Allium bisceptrum can be quite pungent and odorous, they are occasionally used as food flavoring. Before collecting this plant’s leaves, the natives pray. The wild onion bulbs are consumed by numerous animals in the area, including elk, black bears, and prairie dogs. [5] [6][7]
How does damage caused by leaf miners appear?
Although there are numerous varieties of leaf miners, their appearances and plant damage are often the same. Leaf miners are often unremarkable, black flies. The plant is not directly harmed by the flies; rather, the issues are brought on by the insects’ larvae.
This pest is typically recognized by the leaf miner damage. It often manifests as yellow, wavy lines in the leaves. The leaf miner larva practically bore their way through the leaf at this location. Spots or blotches might also be a result of leaf miner damage.
Check your plants regularly
Check young seedlings frequently for leaf mines, especially if leafminers have previously damaged your garden. On the first genuine leaves, mines are most prevalent.
Vegetable leafminers are typically under control thanks to their natural enemies, therefore management is not necessary.
When spinach leafminers attack the leaves of a root crop like beets, no treatment is required. On spinach or another leafy green, however, management may be required.
Keep your garden clean
- Eliminate weeds like lambsquarter to lessen leafminers’ access to it as a feeding source.
- When the mines are small, remove and destroy the leaves.
- After harvesting, till your garden to kill pupae and lessen the possibility that adult flies may move to nearby plants.
Use a physical barrier
- Row covers made of fine-mesh netting should be installed to protect the plants from insects.
- Utilize materials that allow sunlight and rain to reach the plants (e.g. cheese cloth).
- Apply where there haven’t been leafminer issues for at least a year.
- This netting won’t assist if leafminer problems have been noticed during the past year since pupae that survived the winter are inside the row cover and can still infest plants.
- Row coverings are available from numerous neighborhood lawn and garden supply businesses as well as online vendors.
Using pesticides
When pesticides are used, adults are prevented from producing eggs, but larvae that are already eating inside plant leaves are not killed. Select a pesticide with a low environmental impact that does not harm pollinators or natural enemies like parasitic wasps (such as bees).
- Spinosad is an option that may work well. It provides effective control and has little effect on natural enemies because it is generated from a bacterium that lives in the soil naturally.
- Permethrin, bifenthrin, and carbaryl are examples of broad spectrum insecticides that can kill both pests and their natural enemies.
- When adult flies first become active in the spring, insecticides can be used.
- Make sure the leaves are adequately covered.
- Apply a number of treatments on a regular basis (check the label to determine how often you can apply a particular product).
AVOIDANCE: Any mention of a pesticide or the usage of a pesticide label is done so purely for educational purposes. Always adhere to the instructions on the pesticide label on the container you are using. Remember that the law is on the label.
Make sure the vegetable you want to treat is specified on the pesticide’s label before using it. Keep track of how many days pass between applying pesticides and the crop’s ability to be harvested.
Suzanne Wold-Burkness, from the College of Food, Agricultural, and Natural Resource Sciences, and Jeffrey Hahn, an entomologist with Extension
How does the allium leaf miner appear?
The adult allium leaf miner is a tiny, darkly colored insect that measures about 3 mm in length. The female flies produce tiny holes in the tips of the leaves where they lay their eggs in the plant tissue. When eggs hatch into maggots, they tunnel down into the plant to consume and grow.
Barriers To Protect Bulbs
When planting flower bulbs, you should set up a barrier to keep them safe during the winter. You can pick one of the following strategies to help protect your flower bulbs over the winter when you plant your spring bulbs in the fall:
- Chicken-wire netting You can build a cage using chicken wire in which to put your flower bulbs. The holes will prevent annoying rodents from entering while yet allowing the leaves and roots of your bulbs to develop.
- When planting your bulbs, add a layer of sharp-edged gravel or grit below and above them. The majority of animals will stay away from your flower bulbs since they don’t like to dig through pointy objects.
- yogurt cups or strawberry baskets
- You may reuse the green plastic strawberry baskets by poking holes in the bottom of leftover yogurt cups, or you can use these to hold your light bulbs. While all of these techniques will defend your spring bulbs from attacks from below, they may still leave them vulnerable to being dug out from above.
Repellents To Keep Rodents From Flower Bulbs
For already-planted flower bulbs, repellents can be effective. The efficiency of these techniques will inevitably decline with time or inclement weather, thus they must be frequently replaced.
- Blood dinner The typical repellant for flower bulbs is blood meal because it not only serves to keep small rodents away but also helps to enrich the soil with nutrients. The use of blood meal has the drawback of luring unwelcome creatures like raccoons or skunks.
- Animal hair or urine from a predator
- Small rodents can be deterred by scattering animal hair or urine about the location, which will give the place a predatory odor. You can use pee or hair from dogs, cats, or people. You can get dog hair from a dog groomer, human hair from a beauty parlor, and cat urine by sprinkling used kitty litter around the area where your bulbs are planted.
- Cayenne pepper
- Rodents might be discouraged from gnawing on your flower bulbs by using liquid or powdered chili pepper. To deter rodents, liberally sprinkle this flaming substance over the area surrounding your bulbs.
- Plant flavorless bulbs.
- Daffodils, snowflakes, snowdrops, fritillaries, allium, and squill are plants that most rats won’t eat. You can either plant simply these or experiment with interplanting the undesirable bulbs with the more delicate varieties like tulips, crocuses, and gladioli.
What prevents animals from consuming bulbs?
Finding, digging up, and munching tulip bulbs seems to be a specific joy for squirrels and mice. How to keep mice and squirrels away from tulip bulbs: Chicken wire or other large wire mesh works well as a deterrent. Stake it down after placing it directly on top of the bed and extending the surface outward by about 3 feet from the plants.
To safeguard your bulbs from tulip squirrels, you can also place them in wire cages. Put the bulbs in the cage’s center and cover the edges with earth to prevent animals from nibbling on the edges. To keep squirrels away, some gardeners install an old window screen on top of the soil. Tulip plants cannot grow through the screening material like they can through chicken wire, so once the ground freezes, remove it.
Squirrels consuming alliums?
Fortunately, there are a number of things you can do to keep your bulbs where they belong—in the ground. The following techniques can help prevent squirrels and chipmunks from raiding your treasured bulbs, from practical ingredient swaps that will draw attention away from your garden to physical obstacles meant to keep animals at bay.
Cover Your Bulbs
Covering the planting area with chicken wire or hardware cloth is one of the most reliable ways to keep hungry squirrels and chipmunks away from your bulbs (hardware cloth is a metal mesh much like chicken wire except that it has a smaller grid pattern).
To safeguard your bulbs, there are two ways to utilize hardware cloth or chicken wire. A piece of the material that is big enough to cover the entire planting area can be cut. After you have planted the bulbs, set it on top of the dirt and hold it in place with stakes or by weighing it down with rocks or bricks. To conceal the wire, cover the material with a mulch made of finely chopped bark or leaves. The chicken wire or hardware cloth’s holes will allow bulb stems to grow, but the bulbs themselves will be protected from digging animals. The best places for using this method are wide open spaces without perennials or other plants in the way.
Alternatively, you may construct straightforward cages out of chicken wire or hardware cloth, put the bulbs inside, and then bury the whole thing in the ground. These enclosures are particularly effective at keeping out animals that like to burrow, like voles, which also eat bulbs.
Avoid Smelly Fertilizers
The smell of several natural fertilizers, like bone meal, fish emulsion, blood meal, and others, may entice squirrels and chipmunks in addition to digging dogs, cats, and other animals. If your garden has a history of problems with digging animals, stay away from these natural fertilizers and choose instead for synthetic fertilizers that have no odor.
Plant Your Bulbs Among Other Plants
Squirrels have a tougher time finding and digging up spring bulbs when they are planted among established groundcovers or other perennials, such as pachysandra or creeping vinca. The early color your spring bulbs will add to bare spots before the summer perennials start to grow in is another benefit of this method.
Use Natural Repellents
There are a number of natural repellents available that could be quite effective at keeping pests out of your garden. You don’t have to stick to buying organic deer repellents if you want to keep rodents and squirrels away. Red pepper flakes are another successful all-natural squirrel deterrent. Spread liberally over planted bulbs to effectively deter hungry squirrels from digging.
Add Sharp Gravel
When planting bulbs in a garden bed that has already been developed, think about amending the soil with sharp gravel. Squirrels frequently flee an area where they are scavenging when they come across jagged objects. Sharp gravel is available from landscape supply yards or home improvement stores; it is frequently used to provide drainage beneath paved surfaces. Additionally, the unpleasant grit of crushed oyster shells may deter squirrels from digging.
Provide Alternate Food Sources
The idea behind placing a feeding station for squirrels close to your garden is that if the squirrels have easy access to grains and nuts, they won’t try to dig up your bulbs. This approach is debatable; some experts think that providing food only serves to increase the number of squirrels in your yard; they will still destroy your bulbs regardless. However, keep in mind that feeding squirrels and other wild creatures can be against the law in places with especially dense squirrel populations.
Clean Up Your Planting Areas
After you’ve completed planting your bulbs, clean up any plant debris, damaged bulbs you opted not to plant, or outer papery layers that may have come loose from the bulbs. These items can attract squirrels, who will start digging to find other treats you may have left out for them.
Plant Bulbs That Squirrels Don’t Prefer
Some spring-blooming bulbs, like tulips and crocuses, are particularly beloved by squirrels, yet they do not typically consume these plants. Replace your tulips and crocus with less-attractive to squirrels bulbs if you have a serious critter problem, or simply mix them in with your existing bulbs as a deterrent (a few bites of something bitter might keep the squirrels away from your yard). Daffodils, alliums (which also include onions and garlic), scilla, hyacinth, muscari (grape hyacinth), fritillaria, and snowdrops are among the bulbs that squirrels dislike.
Delay Planting Time
Early fall is usually when the squirrel and chipmunk eating frenzy peaks, and by late October, when the rodents have already stockpiled most of their winter food supply, things start to calm down. Plant your spring-blooming bulbs as late in the season as you can, when the squirrels aren’t frantically stocking up for the winter.