Understanding Crop-Protection Products | Plants by J

What This Page Is (and Is Not)

This is an educational reference to help you understand how crop-protection products are categorized and how their active ingredients work. It is meant to help you read product labels more effectively, ask better questions, and make more informed decisions.

This page is not a spray schedule. It is not a substitute for the product label. It does not constitute a recommendation to use any specific product on any specific crop. The label of the specific product you have in hand is the only document that legally governs how that product may be used — including which crops it may be applied to, at what rates, and with what restrictions.

Why Active Ingredients Matter More Than Brand Names

Crop-protection products are sold under brand names, but what they actually contain — the active ingredient — is what determines how they work. Different brand-name products can contain the same active ingredient, sometimes at different concentrations or in different formulations. Some products contain two active ingredients combined for broader activity.

Understanding active ingredients helps you in two ways:

You can recognize when two products share the same mode of action, which matters for resistance management.
You can better understand what a product is and is not designed to do.

However, sharing an active ingredient does not mean two products are interchangeable. Labels differ. Crop listings differ. Concentrations, formulations, and legal use directions can all differ between products that happen to share the same active ingredient.

Always verify the exact label for the exact product in your hand.

FRAC Groups: How Fungicides Are Organized

The Fungicide Resistance Action Committee (FRAC) assigns numeric codes to fungicides based on their biochemical mode of action — how they disrupt the target fungal pathogen. This classification system exists primarily to support resistance management: by rotating between products from different FRAC groups, growers reduce the selection pressure that drives resistant fungal strains.

Here are the categories most commonly encountered in berry and small fruit programs:

Multi-Site Contact Fungicides (FRAC M)

These are broad-spectrum protectants that work on contact with the fungal organism and affect multiple biological processes simultaneously. Because they hit multiple targets at once, the risk of fungi developing resistance is low.

Copper products (FRAC M01): copper hydroxide, copper sulfate, copper oxychloride. Widely used for general disease suppression. Copper is one of the oldest fungicide categories and remains useful as a protectant and for organic programs. It must be applied before infection occurs — it does not move into plant tissue. Various formulations are available for different crops and situations.
Sulfur products (FRAC M02): elemental sulfur, calcium polysulfide (lime sulfur). Used primarily for powdery mildew and as a dormant-season treatment. Lime sulfur has a long history in caneberry and fruit tree programs as a cleanup spray. Sulfur can cause foliar burn in hot weather — label restrictions on temperature at application are important.
Captan (FRAC M04): a broad-spectrum contact protectant used on many fruit crops. Provides moderate to good activity against botrytis, anthracnose, and several leaf spot diseases. As a multi-site material, resistance risk is low.

Strobilurin Fungicides (FRAC Group 11)

The strobilurins (QoI fungicides) are systemic materials with broad-spectrum activity against many fungal diseases. Active ingredients in this group include azoxystrobin and pyraclostrobin. They are widely used in berry programs and are effective against anthracnose, cane diseases, rusts, and several fruit rots.

The key concern with FRAC 11 materials is resistance. Because they act on a single site in the fungal cell, resistant strains can develop if these products are used repeatedly without rotation. This is why extension recommendations emphasize rotating strobilurins with fungicides from other FRAC groups and limiting the number of FRAC 11 applications per season.

DMI Fungicides (FRAC Group 3)

Demethylation inhibitors include active ingredients like propiconazole and myclobutanil. They are systemic fungicides with good activity against rusts, powdery mildew, and certain other diseases. They have limited or no activity against botrytis.

Like strobilurins, DMI fungicides act on a single biochemical target and carry moderate resistance risk. They should be rotated with products from other groups.

SDHI Fungicides (FRAC Group 7)

Succinate dehydrogenase inhibitors include active ingredients like boscalid, fluopyram, and isofetamid. They are often combined with a strobilurin (FRAC 11) in premix products. SDHI fungicides provide activity against botrytis, various fruit rots, and some cane diseases.

Resistance risk is moderate. Rotate with other groups.

Other Single-Site Fungicides

FRAC Group 9 (anilinopyrimidines): includes cyprodinil, pyrimethanil. Activity against botrytis.
FRAC Group 12 (phenylpyrroles): fludioxonil. Often combined with FRAC 9 in premix products. Activity against botrytis and some other fungi.
FRAC Group 17 (hydroxyanilides): fenhexamid. Targeted botrytis activity.
FRAC Group 19 (polyoxins): polyoxin D zinc salt. Botrytis and some other targets.

Phosphonate Fungicides (FRAC Group P07)

Phosphonates (potassium phosphite, fosetyl-aluminum) are used primarily for phytophthora management. They are mobile within the plant and can move downward to roots, which makes them unusual among fungicides. They are not effective against the full range of common foliar diseases — their primary role is oomycete (phytophthora, downy mildew) suppression.

Biological Fungicides (FRAC BM)

Several biological products are registered for use on berries and other edibles:

Bacillus subtilis (strain QST 713): available in products like Serenade. Provides some suppression of botrytis and other diseases. Often used as part of an organic or reduced-spray program.
Trichoderma species: available in products like RootShield. Used as soil treatments targeting root-zone pathogens.
Other biologicals include Streptomyces-based products and plant-extract materials like Reynoutria sachalinensis.

Biological fungicides generally provide lower levels of disease suppression compared to conventional chemistries. They are most effective as part of an integrated program rather than as standalone solutions.

IRAC Groups: How Insecticides Are Organized

The Insecticide Resistance Action Committee (IRAC) uses a parallel classification system. The same principle applies: rotate between groups to manage resistance.

For small fruit and edible crops, common categories include:

Spinosyns (IRAC Group 5): spinosad, spinetoram. Effective against thrips, spotted wing drosophila, and some caterpillar pests. Derived from a soil bacterium. Often acceptable in organic programs (spinosad).
Pyrethroids (IRAC Group 3A): widely available for home and commercial use. Broad-spectrum, which means they also kill beneficial insects and predatory mites. Overuse can lead to mite flares by eliminating natural predators.
Neonicotinoids (IRAC Group 4A): systemic insecticides. Effective against sap-feeding insects. Pollinator concerns have led to significant label restrictions on use during bloom periods for bee-attractive crops.
Oils and soaps (IRAC UN or NC): horticultural oils, insecticidal soaps. Contact-mode materials that smother or disrupt soft-bodied insects and mites. Low toxicity to humans and the environment. Coverage is essential — these only work on contact.
Biologicals: Bacillus thuringiensis (Bt) products for caterpillar pests. Strain-specific — different Bt strains target different insect groups.

How to Read a Product Label

The label is not the marketing copy on the front of the bottle. The important information is on the detailed label, often printed in small type or available as a PDF from the manufacturer.

Key sections to check before using any crop-protection product:

Crops listed: the label specifies exactly which crops the product may be applied to. If your crop is not listed, the product cannot legally be used on that crop, regardless of what a product with a similar active ingredient may allow.
Application rate: specified as amount of product per unit area or per volume of water. Follow the rate. Do not exceed it.
Pre-harvest interval (PHI): the minimum number of days between the last application and harvest. This is a legal requirement and a food-safety measure.
Restricted entry interval (REI): how long after application before people can re-enter the treated area without protective equipment.
Resistance management guidance: many labels include rotation recommendations or maximum number of applications per season per FRAC/IRAC group.
Environmental and pollinator precautions: restrictions on application near water, during bloom, or under certain weather conditions.

A Note on Products and Labels

Products that share the same active ingredient may have different label registrations. One product containing azoxystrobin might be labeled for blueberries; another product containing the same active ingredient at a different concentration or formulation might not be. This is not unusual — it reflects differences in testing, regulatory submission, formulation, and manufacturer decisions.

The practical implication: do not assume that because one product with a given active ingredient is labeled for your crop, all products with that same active ingredient are also approved. Always check the specific product label.

This point bears repeating because it is one of the most common sources of confusion — and one of the most consequential.

Putting It Together: How Growers Actually Use This Information

In practice, experienced growers and extension specialists build spray programs around a few principles:

Start with cultural practices. Variety selection, site drainage, pruning for air circulation, sanitation, and harvest discipline are the foundation. No spray program compensates for poor cultural management.
Use protectants early. Multi-site contact materials (copper, captan, sulfur) applied preventively when conditions favor disease are often the backbone of a spray program.
Add targeted materials during critical windows. Systemic or single-site fungicides from groups like FRAC 3, 7, or 11 may be added during high-risk periods (bloom, pre-harvest) when disease pressure justifies the cost and the risk of resistance is managed through rotation.
Rotate FRAC groups. Do not apply the same FRAC group in consecutive applications. This is the most practical thing you can do to protect the effectiveness of the products available to you.
Follow the label. Rates, timing, crop listing, PHI, and use restrictions are all legally binding and exist for real reasons.
Consult local resources. Extension programs publish region-specific spray guides for small fruits (such as the New England Small Fruit Management Guide, the Southeast Regional Caneberry Production Guide, and equivalents in other regions). These are the best available source of regionally tailored recommendations, including specific products, timing windows, and resistance management notes.

Important Disclaimer

The information on this page is provided for educational purposes only. It is not a recommendation to use any specific product on any specific crop. Crop-protection products are regulated by federal and state agencies. The product label is the legal document that governs use, and it must be followed.

Plants by J does not sell crop-protection products and is not responsible for pesticide use decisions. Always read and follow the label of the specific product you intend to use, and consult your state extension service or department of agriculture for current, region-specific guidance.