Efficacy of selected adjuvants for protecting Spodoptera litura nucleopolyhedrovirus from sunlight inactivation

• Main Authors: Sajap, Ahmad Said, Abdul Bakir, Mohammad, Abdul Kadir, Hussan, Abdul Samad, Norani
• Format: Article
• Language: English
• Published: 2009
• Online Access: http://psasir.upm.edu.my/id/eprint/7034/; http://dx.doi.org/10.1016/j.aspen.2008.12.002
• Institution: Universiti Putra Malaysia

Efficacy of selected adjuvants for protecting Spodoptera litura nucleopolyhedrovirus (SpltNPV) from sunlight inactivation was tested in direct sunlight exposure bioassays and in the field on virus-treated Brassica chinensis var parachinensis plants. All adjuvants, except palm oil, gave significant protection to the virus after 16 h of sunlight exposure, as shown by the larval mortalities. Cumulative mortalities after 14 days show that the virus + Tinopal treatment and the virus not to sunlight treatment attained 100% mortality, while the virus in riboflavin treatment and the crude brown sugar treatment caused mortality of less than 30%. However, the LT50 value of virus + Tinopal was 1.2 times lower than the unexposed virus. All virus-treated plants in the field trials had higher yields and lower damage indices than the control plants. Unlike the results from direct sunlight exposure bioassays, adjuvants, including virus + Tinopal LPW, did not significantly enhance efficacy of the virus against early instars of S. litura in the field. The unformulated virus was as effective as virus + Tinopal LPW and Nurelle-D in protecting the plants from infestation. Thus, in a well-planned pest management program, SpltNPV, without any adjuvant, can be used effectively for controlling S. litura on B. chinensis var parachinensis.