Allium Leaf Miner

[Willie]

If any of you guys are growing garlic, you want to be watching out for this pest. It landed in Pa. in 2014 ish. I first saw a few in 2024's crop. then last years crop was a few more. Most of the damage is in the stalk just above the bulb. But last year I had about 3-4 of them actually get into the clove itself. It's a fly that lays eggs mid march to mid april here and I'm trying floating row covers on the garlic beds during that time frame, this season.

https://cals.cornell.edu/integrated-pest-management/outreach-education/fact-sheets/allium-leafminer

In New York, damage from the ALM is higher in the fall (primarily leeks and scallions) than in the spring (highest damage to scallions). They have discovered that ALM is least damaging to direct-seeded onions and shallots because these crops fall between the two ALM generations. New York growers have experienced the most economic losses caused by allium leafminer with fall leeks and fall scallions and some organic growers have stopped growing these crops.

Allium Leafminer - Growing Small Farms | NC State Extension

Background This spring some growers in the North Carolina piedmont have noticed unusual problems with their allium crops, primarily bulb onions, leeks, and garlic. Obvious above-ground symptoms…

growingsmallfarms.ces.ncsu.edu

My garlic beds now

 

[Bullfrog]

Still have 2 feet of snow on the ground here, itching to get out and get to things. It's going fast was in the 50s yesterday and today, rain later in the week hopefully wipes it out.

Hopefully that cover keeps them out, sounds like it's been successful for some. Sucks to go through all the work and the expectations only to have some damn fly throw a wrench into the works.

 

[Willie]

Still have 2 feet of snow on the ground here, itching to get out and get to things. It's going fast was in the 50s yesterday and today, rain later in the week hopefully wipes it out.

Hopefully that cover keeps them out, sounds like it's been successful for some. Sucks to go through all the work and the expectations only to have some damn fly throw a wrench into the works.

I probably missed it even earlier.so it took 8 years to get here from Lancaster, Pa. which is 3.5 hours sw from here. It got to Lancaster in 2015. Leek growers have it the worst since they are around during both the fly's egg laying periods. Garlic is gone as of July and gets replantd after fly season. Chives are a problem too. Elephant Garlic is a leek actually. I have not seen any probs with those or my chives. These row covers on the garlic might change that, they might get the pressure.

 

[BH]

Allium Leaf MinerCore IPM Strategy (Layered Approach)

1. Physical Exclusion (MOST EFFECTIVE)

• Use insect netting / row covers (0.6 mm or finer)
• Install before flights begin
• Keep sealed at soil edges

This alone can reduce damage by ~90%+

2. Monitoring (Don’t Spray Blind)

• Look for:
  • White feeding punctures (rows of dots)
  • Early squiggly mines
• Use yellow sticky cards to detect adult flights

3. Foliar + Contact Control (Timing is EVERYTHING)
When adults are active (pre-larvae stage):

Rotate these:

• Spinosad (VERY effective on flies)
• Pyrethrins (quick knockdown)
• Azadirachtin (neem-based) (disrupts egg laying)

Spray every 5–7 days during flight windows
Based on your current lineup:

• Evergreen 5.0 (pyrethrin) = solid adult knockdown
• Venerate / Grandevo = mild suppression, better as support—not primary

4. Systemic / Translaminar Options (Key Move)

This is where most people fail.

Because larvae are INSIDE leaves, you need:

• Spinosad (translaminar)
• Abamectin (like Avid) → strong but use carefully
• Cyantraniliprole (if available) → top-tier commercial option

Apply right after first adult damage appears

5. Soil & Lifecycle Disruption

• Remove and destroy infested leaves immediately
• End-of-cycle:
  • Pull all crop residue
  • Don’t compost unless HOT compost
• 
  
• Optional:
  • Beneficial nematodes (limited effect, but can reduce pupae)

6. Crop Timing Trick (Underrated)

• Avoid peak flights:
  • Plant after spring flight ends
  • Or harvest before fall flight

Many pro growers skip entire infestations just by timing
Dialed-In Program (Based on YOUR Setup)

Since you already run a strong IPM system, here’s how I’d integrate ALM control:

During flight periods:
Day 1

• Spinosad drench + foliar

Day 4–5

• Evergreen 5.0 (pyrethrin knockdown)

Day 7

• Azadirachtin or Venerate + Grandevo

Repeat cycle
Add Avid (abamectin) only if pressure spikes


Common Mistakes (Costly)

• Spraying after mines are visible (too late)
• No row cover early
• Not rotating modes of action
• Leaving infested plants in place

Real Talk (Grower Insight)
ALM is one of those pests where:
If you’re reacting, you’re already behind.

The growers who win:

• Block access (netting)
• Hit early (adult stage)
• Keep pressure consistent during flights