Identification of the Sex Pheromone of the Citrus Leafminer (Phyllocnistis citrella Stainton, Lepidoptera: Gracillariidae) with a Trial of Control by the Communication Disruption Method

Abstract

GC-EAD and GC-MS analyses of a pheromone gland extract from virgin females of the citrus leafminer (CLM, Phyllocnistis citrella Stainton) confirmed that the male attractant previously found by random screening tests in a field, (7Z,11Z)-7,11-hexadecadienal (Z7,Z11-16:Ald), is a real pheromone component of CLM. While a field test of lures mixed with extra compounds structurally related to Z7,Z11-16:Ald did not inform candidates for a minor component having a synergistic effect, some compounds, particularly monoenyl derivatives, strongly inhibited the activity of the dienyl pheromone component. Furthermore, two experiments were carried out in citrus orchards to develop a method for disrupting the mating of CLM. In order to estimate the disruptive ability of Z7,Z11-16:Ald and some derivatives, pheromone traps surrounded with septa impregnated with these test compounds were used. However, this first trial was fruitless because the number of captured males actually increased due to the effect of the surrounding compounds such as Z7,Z11-16:Ald. On the other hand, another experiment with polyethylene dispensers containing Z7,Z11-16:Ald revealed a good ability to disrupt the male's orientation, although CLM eggs and larvae on a citrus tender flush did not show any significant difference in the control and treated fields. Monitoring traps caught 27-127 males in one night in control fields from July to September, but hardly any males were caught in either field treated with the dispensers at a density of 500 or 1300 tubes/ha.

Mating Disruption of Citrus Leafminer Mediated by a Noncompetitive Mechanism at a Remarkably Low Pheromone Release Rate

“…In addition, even though it has been proven that a 3:1 blend of Z7Z11E13-16Ald/Z7Z11-16Ald is required for the attraction of P. citrella to traps Moreira et al 2006), the evidence for a noncompetitive mechanism of disruption, such as desensitization or camouflage, suggests that the diene or triene components alone might yield effective disruption. Indeed, Z7Z11-16Ald alone has been shown to effectively disrupt communication of P. citrella in Japan (Mafi et al 2005). Finally, the large acreage of citrus in Florida will demand mechanical application for economic feasibility; therefore, long-lasting formulations amendable to mechanical application should be explored (Stelinski et al 2007).…”

“…In Japan, (Z,Z)-7,11-hexadecadienal (Z7Z11-16Ald) was reported as the behaviorally active sex pheromone (Mafi et al 2005). Brazilian and US populations of P. citrella produce a 30:10:1 mixture of (Z,Z,E)-7,11,13-hexadecatrienal (Z7Z11E13-16Ald), Z7Z11-16Ald, and (Z)-7-hexadecenal Moreira et al 2006).…”

7,11,13-Hexadecatrienal identified from female moths of the citrus leafminer as a new sex pheromone component: synthesis and field evaluation in Vietnam and Japan

“…1) We then confirmed that virgin females actually secrete Z7,Z11-16:Ald. 2) Analysis of the pheromone gland extract showed no other pheromonal components, indicating that this species utilizes a single-component pheromone for mating communication. The dienyl aldehyde, however, attracted no P. citrella males outside of Japan, and a trienyl derivative, (7Z,11Z,13E)-7,11,13-hexadecatrienal (Z7,Z11,E13-16:Ald), 7,11,13-Hexadecatrienal identified from female moths of the citrus leafminer as a new sex pheromone component: synthesis and field evaluation in Vietnam and Japan was recently identified as another sex pheromone component of females collected in Brazil and California.…”

Concise Syntheses of (7Z,11Z,13E)-Hexadecatrienal and (8E,18Z)-Tetradecadienal

“…2 Effective chemical control of the citrus leaf miner is difficult to achieve since the feeding larvae and pupae are protected by the leaf cuticle and the rolled leaf margins. 3 Moreover, the general utility of insecticides is limited by high cost, persistence of residue in tubers, and the environment and development of this insecticide-resistant pest. Considerable efforts have been made for the development and evaluation of new integrated pest-management techniques.…”

“…So the development of new integrated pest-management techniques with pheromone compounds is a very desired goal. 3 The semiochemicals of the pest have been identified as (7Z,11Z,13E)-hexadecatrienal (1, Figure 1), (7Z,11Z)-hexadecadienal, and (7Z)-hexadecenal in a ratio of 30:10:1, respectively. 4 Recently, the synthetic sex pheromone has been used in control of the pest via mass trapping and mating disruption techniques.…”