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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Insect Control and Cotton Disease Research » Research » Research Project #432338

Research Project: Manipulating the Overwintering Diapause of Heliothines with Diapause Hormone

Location: Insect Control and Cotton Disease Research

Project Number: 3091-22000-033-34-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Jan 1, 2015
End Date: Jun 14, 2019

Objective:
Our ultimate goal is to see if we can generate tools to manipulate diapause in members of the Heliothis/Helicoverpa complex. There are a number of ways in which diapause could be manipulated for controlling insects, but few such tactics have thus far been exploited. In working toward this goal with moths in the Heliothis/Helicoverpa complex, we have in past work characterized a neuropeptide, DH, that is highly effective in breaking diapause, and we have now defined the active core of the peptide and developed a hyperpotent agonist that is nearly 50-fold more potent than the native hormone in breaking diapause. This DH agonist also has the capacity to prevent diapause. In addition, we have developed a DH antagonist capable of blocking the diapause-terminating action of DH. Thus, the stage will be set for preventing diapause, as well as both advancing and delaying its termination. It is the goal of this proposal to further enhance the potency of diapause disruptors by generating agonists with even greater biostability and bioavailability, agents that can be consumed by larvae during their feeding stage on the host plant and cause diapause to be averted when the larvae burrow underground to pupate, thus causing ecological suicide. Of similar interest are DH antagonists that could retard the breaking of diapause, or in the extreme, produce a permanent diapause.

Approach:
The work will involve the design and synthesis of biostable, bioavailable analogs of the neuropeptide DH, which regulates aspects of the state of diapause in heliothines, capable of either over-stimulating or blocking the action of this hormone. These analogs will be analyzed by traditional bioassays and in an expressed DH heliothine receptor assay for effectiveness by the cooperating laboratory. These initial assays will be used to guide the development of next generation analogs with further enhanced activity/properties. Analogs with optimal activity and biostable properties will be further investigated for their ability to manipulate diapause in the Heliothis/Helicoverpa complex as a means of controlling these pest insects.