Why Nematodes Can be “Good” or “Bad” for your Garden

Entomopathogenic Nematodes

Ever heard of a NEMATODE? 

You might be more familiar with their colloquial name, which is roundworm. For the purposes of this post, we’ll refer to this creature as a nematode going forward but know that nematodes and roundworms are the same creature. Nematodes are found all over the world and are classified as extremophiles, which means that they have the ability to survive in climates such as polar deserts, the deep biosphere, and inside animal intestines! Wikipedia even lists a species of nematode (Caenorhabditis elegans) as being able to survive atmospheric descent back to Earth’s surface. 

Even though nematodes have a wide variety of quirks and interesting characteristics, you don’t need to make your way to the Arctic Circle to observe these creatures. Nematodes can be found in your backyard—millions per square yard of soil—and they’re commonly divided into two categories: beneficial and harmful nematodes. If you want to keep things simple, good and bad nematodes will also work. 

“Good” Beneficial Nematodes - 

AKA “Entomopathogenic Nematodes”

• Entomopathogenic defines an organism that infects and causes disease to insects. 

Courtesy of BASF

You may be asking how is that a good thing? Fortunately for gardeners and growers, beneficial nematodes primarily target a multitude of soil-based plant pests as their hosts! These nematodes will parasitize and/or kill insects that are harmful to plants and they are considered non-toxic to humans and pets!

There are various species of entomopathogenic nematodes that exhibit different behaviors and pest insect preferences and have been studied in detail for their use against plant pests in agriculture for many years. Because of all of this research supporting their positive impact, the great news for you is that they are commercially reared and available for you to use in your own garden! 

Using beneficial nematodes to control unwanted plant pests reduces the need for
chemical pesticides, which in turn eliminates the frequent harmful byproducts found in commercial pesticides that can cause lasting environmental damage. 

Beneficial nematodes are effective against over 200 common pest insects including grubs, fleas, fungus gnats, beetles, weevils and more! To determine what type is most effective for the pests you are dealing with, you can read this pest selection guide!

“Bad” Nematodes – 

AKA “phytopathogenic Nematodes”

•       Phytopathogenic defines an organism that is parasitic to plants. 

Harmful nematodes, such as root knot nematodes (Meloidogyne incognita) and cyst nematodes (Glob Odera pallida), are notorious for their damaging effects on plants. These nematodes invade plant roots, causing galls and lesions that disrupt nutrient and water uptake. Once infested by the parasitic nematode, the plant will have stunted growth and will begin yellowing. 

Parasitic infections aren’t the only negative effect certain species of harmful nematodes can have on your plants. For example, the root-lesion nematodes of the Pratylenchid genus are known to carry fungal pathogens that cause root rot. As the nematode feeds on the plant’s roots, entry points are created for root rot pathogens. While the overall effects of parasitic and disease-carrying nematodes both result in plant death, disease-carrying nematodes attack plants on two fronts: the physical damage to the plant from root eating and the damage caused by diseases entering the damaged root system. 

What about me? There are nematode species like Ascaris, Trichinella, and hookworms that can infect humans and livestock, but they are very different from the kind that are available for commercial pest control use. These malignant nematodes primarily target and inhabit the intestines of animals causing symptoms ranging from mild gastrointestinal discomfort to severe malnutrition and organ damage. The nematodes discussed above in this post are all species that are harmful to either plants or insects, and they pose no known risks to humans and animals and can be applied without concern near homes, pets and children!

 

By Robin @ ARBICO Organics

Caterpillar & Moth Control

If you think of caterpillars, your thoughts might quickly shift to butterflies. And generally, we all like butterflies! 

• They’re pretty, they’re pollinators, and if you have children, it can be a great experience to monitor a chrysalis to see when a butterfly emerges. 
• The types of caterpillars that become butterflies are welcome in any garden. 

However, there are also caterpillars that become moths! 

Tomato Hornworm

Many of these caterpillars have voracious appetites and will quickly eat through your plant leaves if left uncontrolled. 

Normally, if you’re dealing with clothes or pantry moths, the first thing to do is to put the infected items into a deep freeze (or into the trash if the moths have gotten into your food) then do a deep cleaning. However, when you’re dealing with garden moths and caterpillars, these methods no longer work. Freezing your garden will kill all of your plants, and any type of plant “cleaning” will likely cause a degree of chemical damage to the plant. 

Instead, your best bet is to fight insects with beneficial insects. The beneficial insect in question is the Trichogramma wasp.

 

Before we get into the details of Trichogramma, it’s important to clarify that while they are wasps, they are quite different from yellowjackets and other stereotypical wasps. Trichogramma have no interest in humans, and they cannot sting. Instead, these minute insects, barely visible to the naked eye, are a type of parasite that exclusively targets the eggs of moths and butterflies. A single female Trichogramma can lay its eggs inside hundreds of moth eggs, effectively stopping the next generation of caterpillars before they hatch and wreak havoc on your plants. 

Here’s a quick breakdown of the reasons why Trichogramma wasps are the ideal choice for managing and maintaining moth populations.

A Selective Predator:
Unlike chemical pesticides that can harm beneficial insects and pollinators, Trichogramma only prey on moth eggs. They pose no threat to humans, pets, or even the plants themselves, making them an eco-friendly choice. We said this in the previous paragraph, but we’ll repeat it once more: Trichogramma cannot sting. 

Not a Limited Solution:

By interrupting the moth reproductive cycle at the egg stage, Trichogramma releases provide long-term suppression of caterpillar populations. Regular releases throughout the growing season can help establish a self-sustaining population of these tiny guardians in your garden. ARBICO Organics offers capsule dispensers that will automatically release Trichogramma over a 2 week period.

Effective Against Multiple Moth Species:
Deploy Trichogramma wasps against a vast array of moth and butterfly pests, including cabbage loopers, tomato hornworms, codling moths, and more.

Easy to Use:
This was mentioned in a previous point, but we’ll reiterate the ease of deploying Trichogramma 

wasps. The bugs are available in card and dispenser formats. Place both items around your garden, and combine them with pheromone lures that will bring moth populations to the Trichogramma. 

Won’t Break Your Wallet: 
Compared to the ongoing expense of chemical pesticides, Trichogramma can be a cost-effective solution, especially for long-term pest control.

Robin @ ARBICO Organics

Thrips – How to Protect Your Plants from These Quiet Destroyers

Tube-Tailed Thrips (Phlaeothripidae) in the Center of a Hibiscus Flower

Thrips are tiny, silent plant suckers that can become highly destructive to a garden or greenhouse if left unchecked. Despite their small size, they can do quite a bit of damage as they feed on the more tender parts of plants, including buds, flowers, and new leaves. 

However, not all thrips species are bad. Some can be beneficial, such as preying on other thrips, spider mites, aphids, and whiteflies.

This article aims to provide a comprehensive guide on managing and preventing thrips infestations in an eco-friendly manner.

In this article, you will learn:

• The life cycle of thrips and their impact on plants.
• Early detection techniques for better thrips control.
• Effective strategies to manage and prevent thrips infestations.

Let’s begin by exploring the life cycle of thrips, which is key to effective management.

  Identification and Life Cycle  

Even though thrips are small, they can still be easily identified. They have a uniquely thin body and sometimes have frail-looking wings with feathery fringes. Identifying species can be extremely difficult, but the host plant can often help determine what species of thrips you are dealing with. Even though thrips are hemimetabolous insects, meaning their larval stages look similar to their adult form, they still have four distinct stages:

Egg Stage: 

Thrips Larva

Thrips lay their eggs inside plant tissue, which makes them difficult to detect. The microscopic eggs can be found within the leaves, buds, and stems. 

Larval Stages: After hatching, the larvae immediately feed on plant cells. They are usually white or yellow. 

Pupal Stage: Before becoming adults, thrips enter a pupal stage. This stage often occurs in the soil or hidden within plant debris, making it easy for them to go unnoticed. Some species of thrips will create a cell from silk webbing and pupate inside the cell.

Adult Stage: Adult thrips are mobile and can quickly spread to other plants. They reproduce rapidly, laying more eggs and perpetuating the cycle. Depending on the season and environmental factors, they are both winged and wingless versions of adults.

 
  Damage and Symptoms  

Thrips Damage

Thrips cause damage by piercing plant cells and sucking out their contents. Because
their damage often looks like nutrient deficiencies, the underlying cause can go unnoticed, prolonging the damage and stunting growth.

Silvering of Leaves: As thrips feed, they create silvery or bronze streaks on the leaves, eventually leading to browning and death of the leaf tissue.

Deformed Flowers and Fruits: Thrips feeding on buds and flowers can cause them to deform and grow abnormally, reducing the aesthetic and market value of ornamental plants and fruits.

Stunted Plant Growth: Heavy infestations can stunt plant growth, leading to poor plant health and reduced yields.

Physical Evidence: Besides visual damage, you might notice tiny black fecal spots on the leaves, another indicator of thrips presence.

 
  Monitoring and Trapping  

It’s important to stay vigilant when it comes to inspecting your plants. If you are bringing new plants to your greenhouse or garden, carefully check them for any existing thrips infestations.

You can also use blue or yellow sticky cards to monitor for signs of thrips. Thrips are attracted to these colors and will get stuck on the glue.

 
  Biological Controls  

Leveraging natural predators and beneficial insects can help keep thrips populations in check:

Predatory Mites: Introduce predatory mites, such as Amblyseius cucumeris or Amblyseius swirskii, which feed on thrips larvae. For best results, release before thrips become a serious issue as establishment can take 6-8 weeks.

Natural Predators: By creating suitable habitat for natural predators, you can keep thrips from exploding in growth. Lacewing larvae, minute pirate bugs, and ladybugs are voracious predators of thrips. Release them into your garden or greenhouse to control thrips naturally.

Beneficial Nematodes: To disrupt thrips in the soil, use nematodes to interrupt reproduction and reduce local populations.

 
  Organic Insecticides  

When necessary, use organic insecticides to manage thrips populations. Some effective options include:

Neem Oil: Neem oil disrupts the growth and reproduction of thrips. Apply neem oil as a foliar spray to target both adults and larvae. It can be used before releasing beneficial insects and suppresses foliar diseases like powdery mildew.

Insecticidal Soaps: Insecticidal soaps can effectively reduce thrips populations by suffocating them. Ensure thorough coverage of the plant, especially the undersides of leaves.

Pyrethrin-Based Products: Pyrethrins are natural insecticides derived from chrysanthemum flowers. They are effective against thrips but should be used sparingly to minimize impact on beneficial insects.

Azadirachtin: This spray works like neem oil and can be combined with pyrethrin. Use as a thrips control spray for severe infestations.

PFR-97: This insect-killing fungus has shown great results in controlling thrips and other soft-bodied insects, especially in greenhouses or indoors. It poses minimal risks to beneficial insects and is compatible with most other pesticides.

Thrips can be silent yet destructive pests in your garden or greenhouse. Understanding their lifecycle and impact is the first step toward effective management. By implementing eco-friendly strategies, you can control and prevent thrips infestations while maintaining a healthy garden environment.

By staying vigilant and employing these techniques, you can keep thrips at bay and enjoy a thriving garden all season long.

From Grant @ ARBICO Organics