|NEUMANN, GABOR - University Of Hawaii|
Submitted to: Journal of Asia-Pacific Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2010
Publication Date: 12/1/2010
Citation: Neumann, G., Hollingsworth, R.G., Follett, P.A. 2010. Effect of papaya trunk angle on infestation by white peach scale, Pseudaulacaspis pentagona (Hemiptera: Diaspididae). Journal of Asia-Pacific Entomology. J. Asia-Pacific Entomol. 13:383-385.
Interpretive Summary: White peach scale is a serious economic pest of papaya in Hawaii. We noticed that papaya trees that grow leaning to one side often have higher densities of WPSS on their trunks. Leaning trees occur when farmers plant two trees close to one another. We hypothesized that wind-borne scale crawlers might settle easier on angled trunks compared with upright vertical trunks. Data on trunk leaning (deviation from the vertical line of reference) and white peach scale densities of paired papaya trees were collected approximately one year after infestation of a papaya field was discovered. White peach scale densities were significantly higher on tree trunks that leaned compared with upright trees. Therefore, planting trees close to one another may facilitate the growth and spread of white peach scale populations in papaya orchards, which could result in increased crop loss.
Technical Abstract: Two papaya (Carica papaya L.) seedlings growing in one planting hole often results in angular or non-vertical growth of the trees. Data on trunk angularity, or leaning, (deviation from the vertical line of reference) and white peach scale, Pseudaulacaspis pentagona Targioni-Tozzetti (Hemiptera: Diaspididae), densities of paired papaya trees were collected approximately one year after infestation of a papaya field was discovered. Paired trees showed a significantly higher degree of leaning than single trees. White peach scale densities were significantly higher on tree trunks with a greater departure from vertical in paired comparisons. Therefore, paired tree planting practices may facilitate the growth and spread of white peach scale populations in papaya orchards.