Cutworms are a common pest in vegetables and can cause significant damage to crops, including spinach. These larvae of several moth species can feed on the base of spinach seedlings, causing them to wilt and die. While there are chemical pesticides available to control cutworms, there are also several non-toxic preventive measures that Farmers can take to reduce their populations. This article will discuss some practices for preventing cutworm damage in spinach fields.
Management of Cutworms in Spinach
The Life Cycle of Cutworm
- Egg: The female cutworm moth lays 1200 to 1900 eggs in clusters on foliage. The eggs are initially white but turn brown with age. The egg period lasts for 3-6 days.
- Larva: The larvae hatch from the eggs and go through five to nine instars, with six to seven instars being the most common. The larvae are smooth, cylindrical, and about two inches long when fully grown. They are known for curling into a tight “C” shape when disturbed. The larval stage can last for several weeks to months.
- Pupa: At a depth of 3 to 12 cm, the larvae finally pupate underground. The dark brown pupa is 5 to 6 mm in diameter and 17 to 22 mm in length. There are 12 to 20 days in the pupal stage.
- Adult: The cutworm moth’s wingspan ranges from 40 to 55 mm, making it a pretty sizable insect. The forewing is generally dark brown, with a short black dash running distally from the bean-shaped wing spot and a lighter irregular band in the distal region. The veins on the pale to greyish hind wings have darker scales. The moths will lay their eggs on decomposing plant matter in the absence of low-growing broadleaf plants. The soil is an unfavorable place for oviposition.
Identification of Cutworm in Spinach field
Cutworms are a common pest in spinach fields, and their identification can help determine the appropriate control measures to manage them. The general characteristics of cutworms include their smooth, hairless bodies and tendency to curl into a tight ‘C’ shape when disturbed. However, different species of cutworms may have different colors and markings, making their identification essential.
Damage Symptoms of Cutworm in Spinach Field
- Stems Cut at Soil Level: Cutworms wrap their bodies around the plant’s stem and feed on it, cutting it off just above the soil surface. This feeding behavior can cause young plants to die or slow their growth, leading to reduced yields.
- Damage to Young Plants: New transplants or young plants are more susceptible to cutworm damage because their stems are more tender. Cutworms attack new plants nightly, causing severe damage in the early season when plants are small and have tender tissue.
- Feeding on Leaves and Fruit: Some cutworm species, such as the variegated cutworm, can climb the stem of trees, shrubs, vines, and garden plants and eat the leaves, buds, and fruit.
- Underground Feeding: Some species, such as the glassy cutworm, remain in the soil and feed upon roots and underground parts of the plant.
- Nocturnal Feeding: Cutworms feed in the evening or night and hide in plant debris during the day. This feeding behavior can make their detection challenging.
Management of Cutworm in Spinach by Cultural Method
- Weed control: weeds like lambsquarters and wild mustard can attract egg-laying females and provide food for larvae. Therefore, controlling weeds in and around the spinach field can help reduce the risk of cutworm infestation.
- Fall tillage: Fall tillage can help destroy overwintering pupae. This involves tilling the soil in the fall after harvest to expose the pupae to cold temperatures, which can kill them.
- Debris removal: Removing debris in the vegetable garden that provides cover for cutworms can help reduce their populations. This includes removing plant debris and any other objects that can provide shelter.
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