Hyles lineata Fabricius Lepidoptera Sphingidae

Natural History

  1. This native insect is probably the most widely distributed sphingid moth in North
  2. It is found throughout the United States and southern Canada, and its range extends south into Central America and the Caribbean.

Host Plants. This insect reportedly has a wide host range, but feeds principally on weeds. Its presence among garden plants often results in the assumption that it is developing at the expense of crops when it is actually grazing on an understory of competing plants, especially portulaca, Portulaca spp. If preferred host are eliminated, of course, larvae attempt to feed on nearly any nearby plant. Among vegetables reportedly injured are beet, cantaloupe, lettuce, tomato, turnip, and watermelon. Fruits such as apple, currant, gooseberry, grape, pear, and plum are also listed among hosts. Other plants consumed include bitter dock, Rumex obtusifolius; evening primrose, Oenothera spp.; fuchsia, Fuchsia spp.; four o'clock, Mirablis spp.; and willow herb, Epilobium spp. The adults take nectar from several of flowering plants.

Natural Enemies. Several flies are known to parasitize the larvae, including Compsilura concinnata (Mei-gen), Drino incompta (Wulp), Winthemia deilephilae (Osten Sacken), and W. quadripustulata (Fabricius) (all Diptera: Tachinidae). Although there is no quantitative data on incidence of parasitism, it is evident from the literature that larvae frequently are parasitized by tachinids. Many mature larvae, when collected, are observed to have tachinid eggs adhering to their bodies, usually located dorsally behind the head. Also attacking whitelined sphinx is a pupal parasi-toid, Brachymeria robusta (Cresson) (Hymenoptera: Chalcididae).

Life Cycle and Description. There are two generations annually, with the pupa being the overwintering stage. Adults are usually observed in June and September.

  1. The eggs are oval, and yellow-green initially, but become bluish later in development. They are deposited on host foliage. Eggs normally hatch in 6-7 days.
  2. There are six instars. At hatching the young larva measures about 4 mm long, and measures 6-7, 12-13, 22-23, 37-40, and 55-60 mm long at the start of the subsequent instars, respectively. At maturity, the larva attains a length of 75-90 mm. Development time for the instars is about 8, 4, 5, 5, 4, and 11 days, respectively. During the initial five instars, larvae are green or black, with an yellowish to orange-brown head. The posterior end bears a "horn" that is usually black or yellow and black. A horizontal yellowish subdorsal line is present along each side. Although larvae are fairly variable in color during the early instars,

Whitelined sphinx larva, dark form.

Whitelined sphinx larva, dark form.

Whitelined sphinx pupa.

variation is exceptionally marked in the terminal instar. In the sixth instar the green form has a yellowish-green body with a subdorsal row of pale spots bordered above and below with a black line, and brightly colored spots around the spiracles. The corresponding black form has a blackish body with three narrow yellow lines dorsally. (See color figure 84.)

  1. Pupation often occurs at the soil surface in a loosely constructed cocoon of brown color, but some larvae apparently pupate without forming a cocoon, and some enter the soil to pupate. The pupa is light brown, and measures about 44-48 mm long. Duration of the pupal stage is 30-40 days.
  2. The adults are more active at dusk, but can also be observed feeding during the day, hovering at flowers while sipping nectar. The moth has a wing-span of 60-90 mm. The body is dull brown with white lines, running the length of the head and thorax. The abdomen bears white and dark brown spots dorsally. The olive front wings are marked with white-lined veins and a whitish stripe, extending from the base to the tip of the wing. The hind wings are dark brown, with a rosy band across the middle. (See color figure 219.)

Life history information on white-lined sphinx is quite limited. Soule (1896), Cooley (1905), and Eliot and Soule (1921) provided notes on this species.

Adult whitelined sphinx.

Damage

The mature larvae of white-lined sphinx are quite robust, and can consume large quantity of foliage. However, they normally limit their feeding to portu-laca, moving onto crop plants only when their favored food is completely consumed, and they are faced with starvation. Much of the larva's reputation for damaging crops seems to stem from the habit of resting or nibbling on crop plants. There are no reports of this species completing its larval development on vegetable crops.

Management

Moths are attracted to light, and can be captured in light traps. The presence of adults does not necessarily indicate future problems with crops, however, unless portulaca or another favored weed is also present. Larval infestation of vegetable crops can be avoided by preventing portulaca from growing amongst crop plants. Should portulaca become extensively established, it should not be killed or removed if infested with larvae, as this action will force the larvae to feed on the crop.

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  • NUNZIO
    What spray will kill Hyles lineata?
    6 years ago

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