
Behavior
The number of generations is estimated at four each year in Florida. In northern Florida, moths can be found throughout the year, withstanding several days of freezing weather. ''S. eridania'' larvae are found in northern Florida only in the summer months, which is consistent with most other insects. One generation is about 30 to 40 days.
Habitat
Larvae are defoliators and feed gregariously while young, often skeletonizing leaves. As they mature they become solitary, and also bore readily into fruit, often damaging tomatoes in Florida. It can result in significant yield losses if uncontrolled.Philip A. Stansly, Barry C. Kostyk; Insecticidal Control of Southern Armyworm on Staked Tomato in Southwest Florida, 2015, ''Arthropod Management Tests'', Volume 42, Issue 1, 1 January 2017, tsw131, https://doi.org/10.1093/amt/tsw131 When stressed by a lack of food they will eat the apical portions of branches, bore into stem tissue, and attack tubers near the surface of the soil.
Reproduction
The armyworm has six instars as they grow to attain a length of about 35 mm. Larvae are green or blackish green with uniform light brown or reddish brown through the period of development. Each side has a broad yellowish stripe that has a dark spot on the first abdominal segment. Series of dark triangles are usually present dorso-laterally along the length of the body. Larvae are usually found on the lower part of leaves and are more active at night than during the day. The larval stage usually lasts around 14 to 20 days.References:
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