Spider mites are a common and very annoying pest that affects people who grow cucumbers. These tiny bugs that feed on sap can quickly get out of hand and do a lot of damage to your cucumber plants. You can find important information in this guide on how to find, stop, and get rid of spider mites on cucumber plants.
What Are Spider Mites?
Spider mites are not actually insects, but tiny arachnids closely related to spiders. There are many species, with the two-spotted spider mite being most common. Adults are less than 1 mm long and vary in color from yellowish-green to red.
Spider mites live in colonies, mostly on the undersides of leaves They use needle-like mouth parts to pierce plant cells and suck out the contents. This results in stippling, yellow spots, browning, and leaf loss Spider mites thrive in hot, dry conditions.
Signs of Spider Mite Damage on Cucumber Plants
- Small stippling spots or yellowing on leaves
- Browning and drying of leaves
- Premature leaf drop
- Fine webbing on leaves or stems
If you suspect spider mites examine the undersides of leaves closely. You may see the mites themselves which are just barely visible to the naked eye. Catching infestations early is crucial to protect your cucumber plants.
How to Prevent Spider Mites on Cucumber Plants
Spider mites are hard to get rid of, so avoid getting them in the first place. Here are some important ways to do that.
- Keep plants consistently watered – spider mites thrive on drought stressed plants
- Prune out any infested leaves/stems immediately
- Consider using row covers as a physical barrier
- Release beneficial predatory insects like ladybugs or lacewings
- Avoid excessive nitrogen fertilization which produces soft, susceptible growth
- Wash plants with a strong spray of water to dislodge mites
Safe, Natural Ways to Get Rid of Spider Mites
If prevention fails and mites gain a foothold, act quickly using gentle, non-toxic methods:
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Insecticidal soap: This natural soap disrupts mites’ cellular membranes. Spray cucumber plants thoroughly every 5-7 days.
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Neem oil: Extracted from the neem tree, this oil coats mites to prevent feeding and egg laying. Apply weekly.
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Horticultural oil: These oils smother mites on contact. Use a 1-2% solution, spraying all leaf surfaces.
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Predatory mites: Release mite species that feast specifically on spider mites. They are voracious predators that establish colonies.
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Strong water spray: Blast plants daily with water to detach and kill mites. Pay extra attention to the undersides of leaves.
Focus on getting complete coverage of all plant surfaces when treating. Always follow label directions. For heavy infestations, it often takes multiple applications to get the mite population under control.
When to Use Pesticides for Spider Mites
Spider mites frequently develop resistance to chemical pesticides. When pesticides kill off natural predatory insects and mites, their numbers can actually go up. Because of this, only use pesticides as a last resort when nothing else has worked.
If you must use a traditional pesticide, opt for the least toxic choices like insecticidal soaps, horticultural oils, or neem oil. Spot treat only the most heavily infested areas. After treatment, release predatory mites or insects to reestablish natural control.
Avoid broad spectrum pesticides that kill all insects indiscriminately. Also be aware that many traditional miticides and pesticides are highly toxic to bees. Always follow label precautions carefully.
Removing Severely Infested Cucumber Plants
In cases of severe infestations, the most effective option is often to pull up heavily damaged plants entirely. This curbs the source of the exploding mite population. Just be sure to dispose of the plants immediately in sealed bags or by burning – do not add them to the compost pile.
For milder cases, prune off just the most badly infested leaves and stems. Regularly check surrounding plants and treat at the very first signs of mites before they get out of hand. Early intervention is key.
Spider mites spell trouble for any cucumber grower. The best plan of attack is premised on preventive measures like proper watering, releasing beneficial insects, and prompt removal of early infestations before they spread.
If mites become established, use gentler tactics like horticultural oils and insecticidal soaps. Always target the undersides of leaves. While not a cure-all, these methods help reduce mite numbers so natural predatory insects can take over.
With persistence and a multi-pronged approach, you can gain the upper hand over destructive spider mites and protect your cucumber crop. Just be vigilant in scouting for the very first signs of infestation. By staying on top of spider mites, you can successfully grow healthy, productive cucumber plants.
Conditions that allow spider mites to thrive
Spider mites thrive in hot, dry weather. For spider mites, the best conditions are temperatures in the upper 80s (F) and above, and humidity levels less than 200 percent. However, populations can build up any time humidity is lower than 90%. Every 5–7 days, a new generation of spider mites grows when these conditions last, especially when the nights are warm. Small size that makes mites hard to see and fast population growth combine to make it seem as if large numbers of mites appeared overnight.
Drought-stressed plants are easily damaged by spider mites. In crops where both drought stress and spider mites are present, crop loss of 50% or more is possible.
Mite flare is often attributed to pesticides killing predatory insects and mites that would have otherwise kept the mites in check.
Another situation that contributes to large spider mite populations is the use of particular broad-spectrum chemicals for other insect pests. It is possible for these pesticides to cause mite flare, a condition in which mite populations rise, when they are used to get rid of other pests.
Mite flare is often attributed to pesticides killing predatory insects and mites that would have otherwise kept the mites in check. It can also happen because some insecticides cause mites to reproduce more quickly than they otherwise would (spider mites are not insects). Therefore, consider using “soft” pesticides that are of reduced risk in harming beneficial insects and mites.
Chemicals with low environmental impact
- Insecticidal soap. For soap to be effective, it must cover mites’ bodies. Some leaves may need to be turned over and moved around to get good coverage. Soap must usually be applied multiple times for effective control. Spray the whole plant with soapy water, and then spray it again two or three days later to get rid of any new mites that have hatched (eggs won’t be hurt by the spray).
- Neem oil. Apply as for soap to cover mites’ bodies. Do not use neem oil on plants that are blooming to protect pollinators;
- Both soap and neem oil can hurt plants even more when the temperature goes above 80°F. Before using these products on a plant that is hot, test a small area of it first.
- Chemical Control of Landscape Pests | Pacific Northwest Pest Management Handbooks has a list of specific chemicals that can be used.
- Spider mites can be killed with a number of chemicals that are available to homeowners. The chemical has to come into direct contact with the mites’ bodies in order for it to work. For good control, you usually need to use a thorough spray more than once.
- As always, read product labels carefully. To lower pesticide resistance, use the product exactly as directed on the label. Spider mites are known to become resistant to pesticides when they are exposed to them over and over again. On the pesticide label, there will also be information about the right temperatures for treatment.
How to Grow Cucumbers – Insect Dust & Peppermint Oil Spray Mix: Spider Mites & Cucumber Beetles
FAQ
How do you get rid of spider mites on cucumber plants?
Use a strong jet of water to knock off spider mites from the leaves. Make sure to get the undersides of the leaves where they often hide. Apply insecticidal soap, which suffocates the mites. Make sure to cover all surfaces of the plant. Repeat every 5-7 days as needed. Neem oil is an effective natural pesticide.
What is the best treatment for spider mites?
If a treatment for mites is necessary, use selective materials, preferably insecticidal soap or insecticidal oil. Both petroleum-based horticultural oils and plant-based oils such as neem, canola, or cottonseed oils are acceptable.
Can a plant recover from spider mites?
Plants with mite damage limited to a few leaves will usually recover without special care. But plants stressed by more significant spider mite damage will require extra attention. Make sure your plant gets the appropriate amount of sunlight. Keep soil moisture consistent so the soil is never soggy or too dried out.
Is vinegar good for spider mites on plants?
Step 2: How to Treat Spider Mites on Lucky Bamboo This works for mild infestations. This is effective also: Mix 1/4 cup apple cider vinegar (white vinegar is fine too) with 1 cup of water, 1 t of baking soda & a few drops of mild dish soap into a spray bottle.