Growing tomatillos in Sonoma Valley for decades has shown me that they’re tougher than tomatoes—but not immune to pests or diseases. Fortunately, most problems can be prevented or controlled with simple organic practices. Below is what I’ve learned about the issues most likely to affect tomatillos and the natural solutions that work.

Table of Contents

Common Tomatillo Pests

1. Aphids

Aphids cluster on tender new growth, curling leaves and reducing flowering.

Natural controls I use:

Blast them off with a strong water spray
Release or attract ladybugs and lacewings
Apply neem oil or insecticidal soap early in the evening
Grow cilantro, dill, or borage nearby to attract beneficial predators

I’ve rarely needed more than a couple of soap applications to bring populations down.

2. Flea Beetles

These tiny beetles chew small “shot holes” in leaves, especially early in the season.

Natural controls:

Floating row covers until plants are large
Mulch heavily around the base to reduce soil emergence
Use neem oil weekly during outbreaks
Plant radishes nearby as a trap crop

Healthy, vigorous tomatillo plants usually outgrow the damage once summer heat arrives.

3. Tomato Hornworms

Hornworms don’t target tomatillos as often as tomatoes, but they show up some years.

Control strategies:

Handpick in early morning (my most effective method)
Encourage parasitic wasps by leaving any hornworms with white cocoons
Plant basil nearby to help deter them

Whenever hornworms appear in my garden, I check tomatillos too—they can strip branches quickly.

4. Whiteflies

Whiteflies gather under leaves and cause yellowing and sticky honeydew.

Natural controls:

Yellow sticky traps
Strong hose spray to disrupt colonies
Neem oil or insecticidal soap every 5–7 days until cleared
Improve airflow through light pruning

These are more common in container-grown plants with dense foliage.

5. Cutworms (for young plants)

These pests clip stems at soil level.

Preventive controls:

Use cardboard or foil collars around seedlings
Mulch lightly at first, then increase once stems thicken

I’ve lost a few young tomatillos to cutworms over the years—collars prevent nearly all losses.

Common Tomatillo Diseases

1. Early Blight

Causes brown leaf spots with yellow halos.

Natural prevention and control:

Provide strong airflow through pruning and spacing
Avoid overhead watering
Mulch soil surface
Use copper fungicide if needed during prolonged humidity

In Sonoma’s dry climate, early blight shows up only in late, cool seasons.

2. Powdery Mildew

Appears as white, dusty patches—common in late summer.

Natural controls:

Improve airflow with light pruning
Spray with neem oil every 7–10 days
Apply a milk spray (1:10 dilution) in mild cases
Avoid watering foliage

In container tomatillos, mildew can appear earlier due to tight growth—staying ahead is key.

3. Bacterial Spot

Shows as dark, water-soaked leaf spots that enlarge into brown lesions.

Natural controls:

Remove infected leaves immediately
Avoid working plants when wet
Use a copper fungicide if spreading
Practice crop rotation (avoid planting tomatillos in the same spot annually)

I’ve found that spacing and airflow prevent 90% of bacterial issues.

4. Root Rot

Occurs when containers or in-ground beds stay too wet.

Prevention:

Plant in well-draining soil
Use fabric containers
Water deeply but allow the top layer to dry
Avoid saucers that trap excess water

Once rot sets in, recovery is unlikely—prevention is everything.

Natural Preventive Strategies That Always Work for Me

Rotate crops yearly to avoid soilborne issues
Mulch generously to reduce soil splash and pest emergence
Plant at least two tomatillos for strong pollination and vigorous growth
Prune lightly to keep foliage open and airy
Grow companion plants like basil, borage, marigolds, and cilantro to attract beneficial insects
Inspect weekly—early detection is the easiest organic control

Healthy, fast-growing tomatillos resist most problems naturally, especially in warm-summer climates.