Greens | University of Maryland Extension

Updated: October 23, 2024

Swiss Chard with Leafminers and Seed Maggot Update

Spinach and beet leafminers have been around in low numbers for the past few weeks, which is a couple of weeks ahead of schedule but have increased rapidly in the last 5-6 days. These leaf miners are found in beets, swiss chard and spinach but I usually find them more in swiss chard than spinach. Both of these leafminers are a type of blotch leafminer, creating irregularly shaped mines. These flies attack crops and weeds in the plant family Chenopodiaceae, which includes chard, beets, and spinach and the weed lamb’s quarters. Both fly species are very similar, but the spinach leafminer may also feed on Solanaceous crops such as peppers.

Fig. 1 Leafminer eggs are white and laid on underside of leaves

Updated: October 23, 2024

Red Legged Winter Mites Still Spreading in Leafy Greens Grown in Winter High Tunnels

The Red legged winter mite, Penthaleus dorsalis has been found in more high tunnels (HTs) growing leafy greens this past winter for the 3rd year in a row. Most of the reports I have gotten from HTs are from the Eastern seaboard, but now I am receiving reports from locations further inland, such as Baltimore and Howard counties. Red legged winter mites have dark purple/black bodies and bright red legs (fig. 1). They thrive in what we would normally consider conditions too cold for an arthropod to cause problems.

Updated: October 23, 2024

Spinach Crown Mites in Maryland Spinach

We have had onion and garlic bulb mites and now this same mite group is being found in spinach crowns where they are called--wait for it--spinach crown mites Rhizoglyphus sp. County educator Ben Beale in southern Maryland found crown mites after he inspected damaged spinach plants and mites also were found in northern Maryland spinach fields.

Fig.1 Crown leaves fed on by spinach crown mites are misshapen and ragged with necrotic margins as they expand and in the field the crown leaves are distorted and wrinkled in appearance.

Updated: October 23, 2024

Why are Twospotted Spider Mites Such Problems Lately?

This has been an odd season, like most of them I guess, with lots of rain when we normally have drought and cool temperatures when we normally have heat. We have had problems this year with striped cucumber beetles, hornworms, leafhoppers, squash bugs and surprisingly with twospotted spider mites, Tetranychus urticae (TSSM).

Updated: October 23, 2024

Spinach Crown Mites in Spinach

Updated: October 23, 2024

Spinach Leafminer and Sowbug Damage

In high tunnels and in the field, I have seen spinach or beet leaf miner Pegomya hyoscyami and P. betae respectively in swiss chard and spinach. These leafminers are a type of blotch leafminer, creating irregularly shaped mines (fig.1). Adults are small flies about 1/3 inch in length and gray to brown. Larvae are whitish and cone-shaped. Flies of both species overwinter as pupae in the soil.

Updated: October 23, 2024

How to Build a Low-Cost, Small-Scale Aquaponic System (EM-2023-0698)

Aquaponics is a soilless farming method that combines aquaculture and hydroponics. By combining the two methods the user achieves a mutually beneficial system of plant and fish production that can produce high-yield crops with limited space and water. This factsheet is a step-by-step guide to building a small aquaponics system using repurposed Intermediate Bulk Container (IBC) and parts easily found online or at your local aquarium and hardware stores. Do-it-yourself construction may save farmers money on startup costs and may provide a system with which they can learn and practice aquaponic methods before investing in larger or commercial-scale systems. Authors: Andrea Franchini, Jose-Luis Izursa, Neith Grace Little; Title: How to Build a Low-Cost, Small-Scale Aquaponic System

Updated: October 23, 2024

Beet and Spinach Leafminers

In high tunnels and in the field, I have seen spinach and beet leaf miners Pegomya hyoscyami and P. betae respectively in swiss chard and spinach. These leafminers are a type of blotch leafminer, creating irregularly shaped mines. These flies attack crops and weeds in the plant family Chenopodiaceae, which includes chard, beets, and spinach and the weed lamb’s quarters. These fly species are very similar, but the spinach leafminer may also feed on Solanaceous crops such as peppers.

Leafminer eggs are white and laid on underside of leaf

Updated: October 23, 2024

Swiss Chard and Spinach Leafminers Active

Spinach and beet leafminers have been around in low numbers for the past few weeks but have increased rapidly in the last 5-6 days. These leaf miners are found in beets, swiss chard and spinach but I usually find them more in swiss chard than spinach.

Updated: October 23, 2024

Feeding Damage by Blister Beetles

Normally at this time of year when I talk about any insect problems in crucifers I talk about harlequin bugs that feed by sucking out plant juices and inject toxins into the plant. But I have seen several fields and even some high tunnels with blister beetles feeding and defoliating several different vegetables such as tomato (including the fruit), leafy greens, crucifers, spinach and especially swiss chard (fig. 1). Blister beetles begin feeding on the edges of leaves eventually leaving only stems (fig. 1). The presence of blister beetles now is not unusual as they are often found in large clusters in late summer-early fall. They can arrive in large groups, seemingly overnight and can do a great deal of damage in a short period of time.