Researching Pest Problems
The February issue of Greenhouse Grower included a focus on pest control research in academia. Read on for details on more research.

New Pythium Named
When Carla Garzon, Jeniffer Yanez and Gary Moorman, at the Penn State Department of Plant Pathology, closely examined many isolates of the common crop nemesis Pythium irregulare collected from greenhouses and around the world, they found that these should be separated into 2 distinct groups based on slightly different sizes of structures but very distinct differences in sequences of two DNA sections often used to separate species (the ITS region and the cox II gene) as well as variation in other DNA markers (amplified fragment length polymorphisms or AFLPs).

Based on this information, the name Pythium irregulare (sensu stricto, in the strict sense) was kept to refer to isolates most like the original isolate and the second group received a new name, Pythium cryptoirregulare. ‘Crypto,' referring to ‘hidden' in Latin, indicates that P. cryptoirregulare was hiding within P. irregulare.

None of the Pythium irregulare sensu stricto isolates are resistant to Subdue MAXX (mefenoxam), while many P. cryptoirregulare isolates are Subdue resistant and some are resistant to both Subdue MAXX and Banol (propamocarb). This research, being funded by the Floriculture and Nursery Crops Research Initiative, continues to look for other important differences between these two species.

Optimized Growing Practices
Dr. Kevin M. Heinz is Professor and Head of the Department of Entomology at Texas A&M University. In his undergraduate Floricultural and Horticultural Entomology classes, he provides students with the principles and practices associated with integrated pest management, but also the opportunity to work with Texas growers to improve their pest management programs within their own operations.

The physiogeographic position and climatic conditions in Texas, while favorable for plant production, are also favorable to the invasion of new pestiferous species, proliferation of insect and disease outbreaks and cropping systems requiring high inputs of water and fertilizer to compensate for the warm temperatures and rapid plant growth. The impact of increasing urbanization relative to floricultural and ornamental horticulture crop production are increased markets and availability of a trained work force but with a cost of increasing regulatory policies aimed at protecting the environment and workers, strict management of water quality and availability, and industry competition within global marketplace.
To address the challenges associated with the economical production of quality plant material, management of new and persistent pest problems, and to comply with a changing regulatory landscape, Heinz leads a team of students, research staff, postdoctoral scientists, and interdisciplinary faculty to optimize growing practices for ornamental crops that maximize crop yield and quality while minimizing inputs associated with crop production practices.

The approaches used in accomplishing these objectives are to conduct laboratory, greenhouse and nursery experiments to:

1. study the interactions among crop inputs, crop performance, pest population demographics and population growth, and the performance of various pest management strategies;
2. assess how these interactions influence crop yield and quality;
3. to develop implementation strategies that reduce overall inputs in the U.S. greenhouse and nursery industry while maximizing crop yield and quality.

Web address is http://insects.tamu.edu/people/faculty/heinzk.cfm


Thrips, Whitefly And Fertigation
The following is a summary of research projects conducted at Dr. Luis Cañas' lab at the Entomology Department, Ohio State University.

1. Western flower thrips management options. In a study sponsored by the IR4 project we found that Pylon (chlorfenapyr) was as effective as Conserve (spinosad) at reducing western flower thrips on Gerberas. However, repeated applications will be necessary as the effect of this compound only lasted until 21 days after treatment. Pylon is already available as a miticide but it might become available as a thrips product during 2007.
   
2. Whitefly preference for poinsettia varieties. Another study evaluated the preference and performance of B. tabaci biotype B on different poinsettia cultivars under greenhouse conditions. Although the study needs to be repeated to confirm results and more varieties need to be tested, we found that whiteflies showed some preferences for some cultivars compared to others. There was more oviposition and whiteflies developed faster in one particular variety. Conversely, less oviposition and slower development was observed in another variety. If confirmed, these results will allow us to use these varieties to detect specific plant traits that can confer tolerance of poinsettias to whiteflies.
   
3. Effect of fertilization and irrigation on pest management practices. In one study we evaluated the effect of hot water and insecticidal soap sprays on the two spotted spider mite on Neanthe Bella Palms. It was harder to control the mites with these sprays when higher levels of fertilization were used. In another experiment where we investigated the efficacy of two species of nematodes against fungus gnats we found that the nematodes were effective in reducing the number of fungus gnats emerging but results varied depending on soil moisture. High levels of fertilization and soil moisture that promote pest survival should be avoided to maximize the efficacy of pest management practices.
   
4. Combined effect of whitefly and fungus gnat attack on poinsettias. In this study we found that presence of high fungus gnat populations can worsen attack by whiteflies by promoting higher fecundity and faster development.