Brassica napus Fine Webbing - Causes & Fixes

Jump to cause: Spider Mites (Tetranychidae) Pyralid Moths (e.g., Diamondback Moth larvae) High Humidity and Fungal Hyphae

search Possible Causes

error

Spider Mites (Tetranychidae)

Spider mites are common pests in Brassica napus, particularly in hot, dry conditions. They feed on the undersides of leaves, injecting saliva that causes stippling and leaves behind fine silk webbing as they move between plants.

Very Common

lightbulb

How to confirm: Inspect the undersides of the lower leaves for tiny moving dots or patches of fine, translucent silk.

build How to fix it

shopping_cart Recommended Products

1 Apply an organic insecticide to eliminate existing spider mite populations, eggs, and larvae on the plant foliage.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

$10

In Stock

2 Increase humidity around the plant and avoid hot, dry conditions, as spider mites thrive in arid environments.

3 Carefully inspect the undersides of leaves and remove heavily infested foliage to prevent the mites from spreading to healthy parts of the plant.

warning

Pyralid Moths (e.g., Diamondback Moth larvae)

While often associated with leaf feeding, some larval stages of moths in the Pyralidae family create silken webs to protect themselves while feeding on Brassica foliage. This can be accompanied by visible 'windowpane' damage on the leaves.

Common

lightbulb

How to confirm: Look for small larvae or caterpillars hidden within the webbing or near folded leaf edges.

build How to fix it

shopping_cart Recommended Products

1 Apply an organic insecticide to eliminate larvae and disrupt the life cycle of the moths.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

$10

In Stock

2 Manually remove visible webbing and larvae from the foliage to reduce the immediate pest population.

3 Monitor the plant closely using sticky traps to catch adult moths before they can lay more eggs.

Super Ninja Fungus Gnat Traps - 30 Pack

30 pcs

$7

In Stock

warning

High Humidity and Fungal Hyphae

In extremely humid environments, certain fungal pathogens can create a web-like appearance due to dense mycelial growth. However, this is usually accompanied by visible mold or leaf decay rather than structural silk.

Common

lightbulb

How to confirm: Check if the 'webbing' looks more like fuzzy white mold and if there is an accompanying smell of decay.

build How to fix it

shopping_cart Recommended Products

1 Apply a fungicide to control the fungal hyphae and prevent the spread of mycelial growth across the plant tissue.