Spinich Leafminer- Identification and Management

The adult fly appears in early to mid- May after overwintering in the soil as pupae. It is a about 5 mm long and are gray in color. The adults can be seen flying near the ground between the plants. The females deposit eggs singly or in rows of two to five side by side on the underside of the leaves. In as little as three days but more commonly in four to six days the tiny legless, white to yellowish maggots hatch from the eggs and work their way into the leaf tissue. The maggots feed between the upper and lower leaf surfaces of the host plants mining out the tissue in between. It is not unusual for several larvae to be in the same leaf. As the maggot grows and continues to feed, the mines, which are at first thread-like, become blotch-like and are easily seen on the infected leaves. The larvae are full-grown in 7 to 16 days when they drop to the ground and burrow a few inches into the soil to pupate. Two to four weeks later the adult flies emerge and will soon lay eggs for another generation. In New York you can expect three to four generations each year.
Management- a preventive spray schedule beginning when the spinach is two true leaves and repeated every 7 days. Remove wild hosts like lambsquarter, nightshades, chickweed, and plantain. Deep plowing in the spring can reduce the overwintering population by burying existing pupae. In smaller stands, infected leaves can be picked before the maggots drop to the ground. Removing and destroying these infected leaves can lessen the leafminer pressure
-Ray Range

Upcoming Events
I thought I was covered for that! Farm Insurance Webinar Series, Jan-Feb 2026
January 13, 2026 : Session 1: Insurance and Risk Management 101
Insurance and Risk Management 101. This first webinar will cover many of the general provisions found in insurance policies and describe some of the terms to be aware of when you are considering your options. Steve Hadcock, Capital District Hort Team and Greg Murk, FarmNet.
January 20, 2026 : Session 2: Liability Insurance
Coverage for the risk that your business will cause harm to someone. Are you having people on your farm or selling a food product? You might need liability insurance. Robert Hadad, Cornell Vegetable Program, Elizabeth Higgins, Eastern NY Commercial Hort Program.
January 27, 2026 : Session 3:Protecting Yourself from Disasters (Crop Insurance, USDA FSA programs and Flood Insurance)
Are you protected from a weather event on your farm? Learn about your options for Disaster Coverage (crop insurance, FSA programs, flood insurance). Elizabeth Higgins, Eastern NY Commercial Hort Program.
February 3, 2026 : Session 4: Insuring People (health, life and disability insurance)
Options for health insurance, life insurance and disability insurance, and how they can help farmers and their employees. Maire Ullrich, CCE Orange County and Lucas Smith, Cornell Ag Workforce Development
February 10, 2026 : Session 5: Property Insurance
Insuring your infrastructure, equipment, and livestock from loss. Learn about the types of coverage, and the risks they reduce. Colin Hostetter, Tri-County Ag Team, Desiree Keever, CCE Delaware County and Steve Glick, Kevin Daniels Agency.
2026 Cornell Winter Fruit Webinar Series
January 22, 2026 : Blueberry Pruning and Soil Health to Minimize Pests and Maximize Yield
Week 1: Blueberry Pruning and Soil Health to Minimize Pests and Maximize Yield
January 29, 2026 : Cost of Production for Fruit Crops
Week 2: Cost of Production for Fruit Crops - A new tool for tree fruit, updates on berry production in NY, and strategies for tracking and using expense data
February 12, 2026 : Fire Blight Management Updates
Week 3: Fire Blight Management Updates - Pathogen Biology, Defense Inducers, Biopesticides, and Pruning Therapies
February 19, 2026 : Pink and Petal Fall Insecticides- Can We Strike the Right Balance?
Week 4: Pink and Petal Fall Insecticides - Can We Strike the Right Balance?
March 12, 2026 : Inoculating Orchards with Mycorrhizal Fungi
Week 5: Inoculating Orchards with Mycorrhizal Fungi
March 19, 2026 : St. Peachtrick's Day - Cherry Pruning Strategies and Plum Varieties for the Northeast
Week 6: St. Peachtrick's Day - Cherry Pruning Strategies and Plum Varieties for the Northeast
How to Diversify or Scale Up with Confidence for Profitability - Inspired by Annie's Project
February 4, 2026
February 11, 2026
February 25, 2026
Do you have an idea for a new enterprise to add value to your farm? Maybe you're considering scaling up for a potential market opportunity but just aren't sure if it's a good fit for your business. Join Cornell Cooperative Extensions of Allegany County, Broome County, Madison County, Onondaga County, Niagara County, Tioga County, the Niagara Small Business Development Center, and the Eastern NY Commercial Horticulture Team for a hybrid series on Wednesdays in February, starting on February 4th that will answer these questions and more. Annie's Project seeks to empower farm women through education, networks and resources. We welcome, and encourage, learning and sharing amongst farm women as we help you grow as decision-makers and leaders on your farm.
