Potential of entomopathogenic fungus, Isaria fumosorosea to protect potted ornamental plants against Bemisia tabaci during shipping

Authors: OSBORNE, LANCE - UNIV OF FL, IFAS, MREC; LANDA, ZDENEK - UN OF S BOHEMIA STUDENTSK; BOHATA, ANDREA - UN OF S BOHEMIA STUDENTSK; McKenzie, Cindy

Submitted to: International Organization for Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2008
Publication Date: 7/28/2008
Citation: Osborne, L.S., Landa, Z., Bohata, A., McKenzie, C. 2008. Potential of entomopathogenic fungus, Isaria fumosorosea to protect potted ornamental plants against Bemisia tabaci during shipping. International Organization for Biological Control/West Palaearctic Regional Section Bulletin. 32:159-165.

Interpretive Summary: Introduction of non-indigenous species have increased with expanding global trade. Also, many indigenous plant pest species are disseminated on infested host plants through foreign and national trade during shipping. Effective precautions aimed to prevent or minimize involuntary human-mediated introduction of pests into new regions are therefore required. Whiteflies represent a typical group of pests that can be disseminated with host plants shipped from one area to another, mainly due to the close relation immature stages have with their host plants. Strict rules were developed and applied recently to prevent the dissemination of the silverleaf whitefly, Bemisia tabaci, which may have significant negative impact on trade negotiations and which increase the costs of protective programs. This is particularly true when special pre-shipping treatments must be applied to eradicate whiteflies before and during shipping. This case study’s objective was to evaluate the eradication capability of an entomopathogenic fungus Isaria fumosorosea (formerly Paecilomyces fumosoroseus) when used to protect poinsettia plants against whitefly infestations. The research showed the fungus to be very effective. The significance of these results is important from the standpoint that we now have data to support the efficacy of pre-shipment treatments of ornamental plants with an insect pathogenic fungus. These treatments will, when combined with current management requirements, add an additional level of insurance that plants will not be shipped infested with living whiteflies. The next studies to be conducted will include similar evaluations against whitefly eggs, which are known to be susceptible to this fungus. We will also, if additional funding and permits are secured, validate these results with reciprocal shipments of infested plants between quarantine facilities in the United States and Czech Republic.

Technical Abstract: The efficacy of entomopathogenic fungus Isaria fumosoroesa has been evaluated under abiotic conditions similar to those typical for shipping of ornamental plants. When applied to a synchronized population of B. tabaci L4 nymphs on poinsettias, I. fumosorosea induced mortality even in regime of low temperature. The efficacy of this fungus was increased by dose, application of pre-germinated conidia and additional nutritional supplements. In some treatments, the population of B. tabaci was practically eradicated and there were no symptoms detected which would indicate a fungus related phytotoxicity. The significance of these results is important from the standpoint that we now have data to support pre-shipment treatments of ornamental plants with an insect pathogenic fungus. These treatments will, when combined with current requirements add an additional level of insurance that plants will not be shipped infested with living B. tabaci.