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Leafy Greens (Arugula) Pests



Figure 11.1Cabbage aphids are oftenseen congregating on host crops; note their white-gray waxy coating.

Figure 11.2 Green peach aphids varyin color including yellow, green, dark green, pink, and red.

Figure 11.3Potato aphids can be pink or green in color.

Figure 11.4Aphid feeding can cause host plant leaves to curl.

Aphids

Cabbage Aphid (Brevicoryne brassicae)

Green Peach Aphid (Myzus persicae)

Potato Aphids (Macrosiphum euphorbiae)

DESCRIPTION:

Adult: Soft, pear-shaped body with tailpipe-like appendages called cornicles on the rear of the body. Adults range in color from yellow, green, orange, and pink depending on the species, time of year, and food source. Cabbage aphids have a white powdery wax covering their bodies and are green to gray in color.
Egg: Initially yellow or green, becoming shiny-black as they mature.
Nymph: Similar in shape and color to the wingless adult, but smaller.

LIFE HISTORY:

Most vegetable aphid species have similar life cycles.
Cabbage aphid overwinters primarily as eggs on debris of cole crops, mustard family plants, or related weed species, and in southern Utah, they may overwinter as adults. Green peach aphid overwinters as eggs on peach, nectarine, apricot, and plum trees. Potato aphid  overwinters as eggs on wild and ornamental rose plants. Eggs hatch as all females in spring. Adults reproduce asexually, give live birth, and have 2-16 generations. They move from overwintering hosts to vegetable crops and/or weeds for the summer. Winged, migrant aphids develop when food quality declines, crowding occurs, or when they are seeking new plant hosts. In late summer to fall, aphids reproduce sexually to lay eggs for overwintering. Potato aphid populations are generally highest in the spring and fall.

DAMAGE:

Aphids contaminate plant parts, leaving them unmarketable. Their feeding may cause stunted, yellowed, distorted, and/or curled leave and loss of plant vigor. Aphids secrete a sticky substance called honeydew, on which sooty mold fungi may grow.

MANAGEMENT:

Cultural:

        • Avoid excess fertilization. Aphid densities tend to be higher on plants that have an excess of nitrogen fertility
        • Use mulches or row covers. Reflective mulches and row covers can help reduce aphid populations on vegetables by interfering with the ability of winged aphids to find plants.
        • Remove/destroy plant debris. Disking fields immediately after harvest will destroy alternate host plants and reduce available aphid and virus sources.

Chemical:

Many aphid species in other parts of the world have developed resistance to multiple insecticide groups, including some synthetic pyrethroids, carbamates, and organophosphates. In Utah, use these insecticides sparingly; instead choose products that are less damaging to natural enemies of aphids and non-target insects.

Biological:

Natural enemies include lady beetles, lacewings, syrphid flies, and parasitic wasps play a major role in the natural suppression of aphids.