Corn earworm moths

Kingan T. G., Bodnar W. M. and Hunt D. F. (1995) The loss of female sex pheromone after mating in the corn earworm moth Helicoverpa zea identification of a male pheromonostatic peptide. Proc. Nat. Acad. Sci. USA 92, 5082-5086. 

The object of the work described here was to measure the amount and distribution of pheromone vapor in the air under woodland canopies after aerial applications of slow release formulations of disparlure, and the rate at which these declined with time. A limited number of experiments have also been done Z-9-tetradecenol formate (TDF), a mating inhibitor for the corn earworm moth (Heliothis Zea). 

We observed that when adult females of the corn earworm moth (Heliothis zea) were ligated between the head and thorax so that normal hemolymph circulation between the brain and the rest of the body was interrupted, they did not produce sex pheromone. However, the ligated females could be stimulated to produce pheromone, in amounts not different from that produced by normal females, by an injection of a saline extract of the female brain. Our studies with this nocturnal moth indicate that the neurohormone is stored in the brain and released into the hemolymph in the scotophase causing timely production of pheromone by the female. 

Figure 1.1 The three major types of hormones that regulate pheromone production in insects. A Juvenile Hormone III (C16 JH), B 20-Hydroxyecdysone and C PBANs from the corn earworm, Helicoverpa zea (Raina et al., 1989), the silkworm moth Bombyx mori (Kitamura et al., 1989) and the gypsy moth, Lymantira dispar (Master et al., 1994). The minimum sequence (pentapeptide) required for activity is indicated.

Adding to the puzzlement of this system, we found that pheromone production could also be induced in the glands of ligated corn earworm females by injection of brain extracts of the male corn earworm and extracts of females from four different families of moths (Pyralidae, Lymantriidae, Geometridae, and Psychidae) (27). The sex pheromones of females representing these families have little or no chemical similarity to the corn earworm sex pheromone... 

Ryania is made from the ground roots of the tropical shrub Ryania speciosa. The active principle of ryania is the alkaloid ryanodine (C25H35NOu). Ryania is used for controlling aphids, cabbage loopers, Colorado potato beetles, diamondback moths, cucumber beetles, leafhoppers, corn earworms, European corn borers, codling moths, citrus thrips, and so on. Its oral LD30 in rats is 1200 mg/kg so it is practically nontoxic to mammals. 

Mating in most species of moths is mediated through the production and release of species-specific sex pheromones by the females and, in a majority of the moths, reproductive activity is limited to the hours of darkness. To achieve this diurnal periodicity of mating, production of sex pheromone must also be synchronized (JL). In the corn earworm, Helicoverpa Heliothls) zea, and in many other species of moths, this synchronization is affected by a factor produced in the head of the female (2.). The factor was identified as a peptide hormone, produced in the suboesophageal ganglion (SOG) and most likely... 

We recently reported the primary sequence of the pheromone biosynthesis activating neuropeptide hormone (Hez-PBAN) that controls sex pheromone production in adult female moths of the corn earworm. Heliothis zea (1), Hez-PBAN is a 33 residue C-terminally amidated peptide with a molecular weight of 3900 daltons. This paper describes the details of the isolation and characterization of this first member of a new family of insect neuropeptides. 

Causes Corn earworms European corn borers fall armyworms. Leaves and silk may be chewed. Stalks and tassels may be tunneled and may snap off. Corn earworm larvae are light yellow, green, pink, or brown caterpillars up to 2" long, with lengthwise stripes. Adults are tan moths. See page 77 for an illustration of this pest. 

Ryanodine is the active, insecticidal ingredient of a tropical shrub Ryania speciosa). For years, this botanical insecticide has been recommended for use against citrus thrips, corn earworms, European corn borers, codling moths, and a variety of other pests. However, ryania is also quite toxic to mammals and water life. For this reason, it s better to rely on safer pest control measures,. such as iasecticidal soap, neem, or pyrethrin. 

In a few Lepidoptera, like the silkworm moth Bombyx mori), hehothide species as the corn earworm (Helicoverpa zea) and the cabbage moth (Mamestra brassicae) it has been demonstrated that a neuronal hormone (PBAN, pheromone biosynthesis activating neuropeptide) is synthesised by a cephalic organ in their brain, dependent on the day/night rhythm. This mediator controls the sex pheromone production in these moths. [161, 170]... 

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