Gail Ruhl and Karen Rane
Interim P&PDL Co-Directors/Senior Plant Disease Diagnosticians

The mission of Purdue's Plant and Pest Diagnostic Laboratory (P&PDL) is to provide accurate and rapid identification of plants, pests, and plant problems; suggest management strategies, when requested; and serve as a source of unbiased information for plant and pest related problems.

The staff of the Plant and Pest Diagnostic Lab, along with other cooperating Extension Specialists in the Departments of Botany and Plant Pathology, Agronomy, Entomology, and Horticulture diagnosed a total of 2590 problems (Table 1) on the1726 samples in 2005 (Table 2).

Of the 1726 sample submissions to the P&PDL, 1632 were submitted as physical samples, 20 were submitted as digital images accompanied by physical samples and 74 were submitted strictly as electronic submissions of digital images to the Lab via a standard web-based method.

The majority of routine samples were received by the P&PDL during the months of June, July, and August (Figure 1). Same day service was provided for 8% of the samples received during 2005 and 38% of the samples were completed in three days or less. A total of 65% of the samples received during 2005 were diagnosed within five working days and 90% of all samples received were answered within 10 working days. An extended turn-around time of greater than 10 days (10% of samples) was documented for those samples requiring more extensive culture work and laboratory testing (Figure 2).

Noninfectious disorders (40%), infectious diseases (39%), and arthropod-related problems (14%) were the most common primary diagnoses in 2005 (Figure 3). The most common commodities submitted to the P&PDL were ornamentals (52%) and agronomic crops (26%) (Figure 4). The remaining 22% of samples were distributed among various other commodity groups including turf, vegetables, fruit, specialty crops, and insect, fungal , and aquatic weeds identification. Purdue Extension Specialists and Research Associates provided commodity related summaries of prevalent problems that occurred in 2005.

The Plant and Pest Diagnostic Laboratory (P&PDL) serves as the plant disease diagnostic facility for the Indiana Department of Natural Resources (IDNR) and thus, the P&PDL and IDNR work together during outbreaks of diseases of regulatory concern. In 2005, P&PDL and IDNR staff worked cooperatively to survey nurseries for the presence of Phytophthora ramorum, a disease of regulatory concern. All 801 samples collected from the 20 Indiana nurseries surveyed tested NEGATIVE for the presence of P. ramorum.

In cooperation with the IDNR, the P&PDL also provided disease diagnosis on 86 corn and 9 soybean samples for IDNR's Phytosanitary Certification Program, as well as confirmation of Peronospora tabacina on tobacco samples as a part of the IDNR 2005 Indiana Tobacco Blue Mold Field Survey.