If your plants look stunted and its leaves exhibit chlorosis and lack vigour, yet you’ve done everything right and you can’t figure out why, it’s time to check the roots of your plants. If the roots are knobbly and have galls, you have a case of root knot nematodes in your soil. I have experienced this on a few occasions, fortunately in my planters and not in-ground. Read on to find out how to control root knot nematodes organically.
What are they? These plant parasites are microscopic roundworms that damage plant roots and feed on its vascular system. This causes growths to form, affecting the plant’s capacity to absorb water and nutrients.
Shrubs, trees and herbaceous plants are susceptible to root knot nematodes. These include begonia, azalea, hibiscus, gloxinia, hydrangea, impatiens, cyclamen, coleus, some cacti, rose, and edible plants like tomato, capsicum, chilli, eggplant, rosella, okra, cucumber, pumpkin, melons, Malabar spinach, passionfruit, banana, pineapple, sweet potato among others.
What are your natural options? Here’s how to get rid of root knot nematodes organically, you can consider using a mix of methods to improve efficacy rates.
Opening your back door to see your prized African daisies in full bloom is a heartwarming sight. But discovering those delicate flowers and leaves distorted and damaged can make your heart sink One tiny culprit behind such destruction is the microscopic nematode Getting rid of these nearly invisible roundworms takes some know-how. But with smart organic tactics, you can tackle nematodes and enjoy carefree African daisies again.
Understanding Nematodes – The Microscopic Worms
You need a microscope to see the slender nematodes slithering through your soil and plant tissue. Over 4,000 species of these microscopic worms exist, most harmless, but some parasitize plants. The root-knot, sting, and stubby-root nematodes munch on roots, disrupting water and nutrient flow.
Above ground, foliar nematodes pierce leaf cells, causing spots, wilts, and distortions. An infestation slowly sucks the life out of your African daisies, stunting growth and ruining that vibrant beauty. Know your enemy by having soil tested or examining plant roots and leaves. Catching infestations early makes eliminating nematodes easier.
Organic Amendments – Enhancing Beneficials
Adding organic amendments like compost, manure, chitin, or neem meal to the soil is an effective eco-friendly method of reducing nematode damage. These nutrient-rich materials have complex effects on the intricate soil food web. As they break down, populations of beneficial predatory nematodes and microbes explode, attacking pest nematodes.
Organic amendments also strengthen plant cells, making them more resistant to nematode penetration. Compost and manures also nurture plants with a slow-release feast of nutrients to recover from nematode damage. Well-fed, vigorous plants better withstand and outgrow nematode pest pressures.
Solarization – Baking Away Nematodes
Solarizing your African daisy’s soil with a plastic sheet mulch harnesses the sun’s power to wipe out nematodes. This chemical-free tactic elevates temperatures under the plastic to levels lethal for nematodes while avoiding harming beneficial organisms deeper in the soil.
First, water the soil, then lay down clear plastic, sealing the edges well with soil. Leave the plastic in place for 4-6 weeks during the hottest weather. The soil solarization process pasteurizes the top 4-6 inches of soil, decimating nematodes without damaging soil health. Just be sure to remove plastic debris afterward.
Crop Rotation – Starving Nematodes
Since many nematodes favor specific plant hosts, rotating crops is an excellent cultural control. Avoid planting African daisies or related species in the same soil two years in a row Give nematodes nothing to feed on by alternating plant families in the bed each season
For example, swap between daisies, beans or peas (legumes), onions or lettuce (alliums and leafy greens), and carrots or radishes (root crops). Disrupting nematodes’ food source starves out populations so rotating crops bolsters your other nematode busting efforts.
Resistant Varieties – Blocking Access
Some African daisy varieties have natural genetic resistance to nematodes. Instead of nematode-vulnerable open bloom hybrids, choose resilient varieties like ‘Cape Daisy,’ ‘Blue-eyed Daisy,’ or ‘Climax.’ Resistant African daisies have physical and chemical barriers that hinder nematodes from penetrating leaf and root tissues.
This genetic armor prevents nematodes from occupying plant cells and doing damage. Combining resistant varieties with other organic controls like solarization or amendments stacks the odds against nematodes even more in your favor.
Trap Crops – Luring Nematodes Away
Divert nematodes away from your precious African daisies by planting sacrificial trap crops. Certain plants like marigolds, mustard, and rapeseed work well. The trap crops lure nematodes to colonize their roots instead of your daisies About 6-8 weeks later after heavy infestation, pull up and destroy the trap crops along with the nematodes
Time new trap crop plantings to coincide with periods of high nematode pressure. Use trap crop rotations annually to reduce nematode numbers gradually over time. This pull, not push, approach leverages natural nematode behavior against the pests.
Organic Fertilizers – Strengthening Plant Defenses
Whipped up from ingredients like manure, bone meal, and alfalfa, organic fertilizers slowly release a feast of nutrients to feed your soil. Robust microbial activity unlocks the bounty of minerals, nitrogen, and phosphorus to nourish plant growth. Well-fed African daisies produce more root exudates that support armies of beneficial nematode-killing bacteria and fungi.
Organic fertilizing also strengthens the plant’s natural structural defenses against nematodes. Thicker cell walls prevent the worms from invading while pumping up production of nematode-repelling compounds. The key is applying organic fertilizers at the right time when plants can use the nutrients most effectively.
Beneficial Nematodes – Fighting Fire with Fire
Fighting microscopic foes with beneficial microscopic friends is a proven biological tactic. Beneficial nematodes seek out and infect pest nematodes, acting as a living insecticide. Safe for people, pets, and plants, they come packaged and stored in sponges or gels for easy application.
Follow product instructions carefully for best results. Beneficial nematodes require adequate soil moisture and proper temperatures to hunt effectively. Time applications when susceptible pest stages are present. Combining beneficial nematodes with other controls like crop rotation or resistant varieties overwhelms nematodes on multiple fronts.
Neem & Essential Oils – Confusing and Repelling
Extracted from the neem tree, neem oil and cake deter nematodes in several ways. Azadirachtins, the active compounds, confuse nematodes so they can’t locate plant roots or mates. Neem also paralyzes worms and disrupts their growth so they can’t reproduce or feed normally. The oil’s strong aroma also repels nematodes.
Essential oils like garlic, mint, rosemary, and thyme oil work through similar nematode-repelling properties. Just mixing a few drops in water and spraying the soil or adding neem cake when planting offers protection. The oils’ lingering odors mask root scents and confuse nematodes’ hunting instincts.
Soil Health Focus – Bring on the Microbes!
The state of your soil significantly influences nematode populations. Unhealthy, low organic matter soils with minimal microbial activity favor higher nematode numbers. But practices promoting diverse soil life keep nematodes in check naturally. Regular additions of aged compost feed soil microbes that compete with or consume nematodes.
Avoid synthetic fertilizers and chemicals that kill off beneficial organisms, reducing natural biocontrol. Limit soil disturbances like frequent digging or tilling which damages fungal hyphae networks. Protect your soil’s ecosystem and the microbes will help manage nematodes.
An Ounce of Prevention – Starting Nematode-Free
Check any new plant additions to ensure they are nematode-free before introducing them to your garden. Carefully inspect root balls and avoid plants with knots or stunted roots. Start seeds in sterilized soil or potting mix rather than possibly contaminated garden soil. Screen compost piles to prevent accidental nematode introduction.
Sanitize gardening tools after working in nematode-infested areas. Removing weed hosts and crop debris which may harbor nematodes also minimizes sources. Take a proactive approach to keep nematodes out rather than battling an established infestation later. Prevention is the best medicine!
With a multi-pronged game plan blending cultural, physical, and biological tactics, you can knock back nematode pests and enjoy carefree African daisies. Patience and persistence are vital since there are no quick fixes for nematode control. But the reward of vibrant blossoms and thriving daisies will make your efforts worthwhile.
Grow biofumigant crops for root knot nematode control (Photo by
Brassicas such as Brassica rapa (field mustard) and Brassica juncea (mustard greens) have bio-fumigation properties and are effective at root knot nematode control when grown as a cover crop, however there are some other plants, like Tagetes patula (French marigolds), Tagetes erecta (Mexican Marigold) and oats, which are highly capable too.
How it works is it releases compounds to suppress pests and pathogens in the soil. It is effective when in its early flowering stages, plants are chopped or pulped and incorporated into the soil and watered. The soil needs to remain moist for a few weeks, and isocyanate gases are released by the plants as it breaks down.
Not all plants are susceptible to root knot nematodes. Through rotating the types of plants grown over two years or more, specifically incorporating plants that are not host plants, you can starve these nematodes. Root knot nematode resistant plants include corn, millet, grain sorghum, asparagus, and chrysanthemum and zinnia.
Add compost and organic matter
Good quality aerobic compost contains plenty of microbes. These include larger, predatory micro-organisms, including beneficial nematodes that can ingest root knot nematodes. By applying it directly as a top dressing or some prefer, compost tea, these microbes are introduced into the soil. Adding organic matter such as manure and leaves also encourages fungi, bacteria and naturally occurring good nematodes to inhabit soil.
In Singapore, you can get good quality compost from Soil Social, it is more pricey than other composts on the market, however it is aerobic and contains a high amount of beneficial microbes. I tried it and have seen improvements in my plants as soon as within a month. My stunted okra grew more lush and began fruiting more regularly.
You can also consider trying out this soil drench recommended by Jerry Coleby-Williams of Gardening Australia.
This method makes it very inhospitable for root knot nematodes, however it kills many organisms in the process, including pathogens, nematodes, weeds, and seeds. Soil solarisation involves laying clear (more effective) or black plastic sheets over wet soil for 4-6 weeks, therefore trapping heat and raising soil temperature. Nematodes are mobile, so this method will reduce numbers but it may not fully eradicate the population.
How To Get Rid Of Nematodes | Eliminate Bad Nematodes and Grubs Organically!
FAQ
What kills nematodes naturally?
What repels nematodes?
Does vinegar kill nematodes?
What insecticide kills nematodes?
|
Chemical name
|
Trade name
|
Formulation
|
|
Thionazin
|
Nemafos
|
Granular or emulsifiable liquid
|
|
Ethoprophos
|
Mocap
|
Granular or emulsifiable liquid
|
|
Fenamiphos
|
Nemacur
|
Granular or emulsifiable liquid
|
|
Fensulfothion
|
Dasanit
|
Granular
|