Impact of Feeding by Tomato Fruitworm, Heliothis zea (Boddie) (Lepidoptera: Noctuidae), and Beet Armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), on Processing Tomato Fruit Quality

TLDR: Differences in seasonal damage and damage at harvest were observed between weeks, between levels of infestation, and between the week × level interaction for all of the third-instar H. zea larval infestations.

Abstract: Artificial infestations of Heliothis zea (Boddie) and Spodoptera exigua (Hubner) were made on three field plantings of processing tomatoes on a weekly basis in 1982 and 1983 to establish the damage relationship between infestations of each species during the season and damage at harvest. Comparisons of damage by both species were made to determine differences by week, level of infestation, and the week × level interaction. Damage was higher in the sampled plots during the season than in plots infested at the same time but sampled for damage at harvest. In general, the amount of damage recorded at harvest was greater as the date of infestation approached the harvest date. Differences in seasonal damage and damage at harvest were observed between weeks, between levels of infestation, and between the week × level interaction for all of the third-instar H. zea larval infestations, but only for the highest infestation levels of third-instar S. exigua . During 1982, when lower infestation levels were used, differences in damage due to timing of damage were not significant, although the general pattern held. During 1983, late instars were used, resulting in less mortality, higher levels of damage, and less variable damage.