The Plant and Pest Diagnostic Laboratory (P&PDL) at Purdue University is an interdisciplinary laboratory dedicated to providing accurate and rapid identification of plant diseases, insects, weeds and cultural problems. We serve as a source of unbiased information regarding pest management strategies and provide training for plant and pest related problems.

We provide diagnostic services to county extension educators, agricultural consultants, growers, dealers, distributors, landscapers, homeowners, nursery and greenhouse operators. University research faculty and staff and inspectors associated with the Office of the State Chemist and the Entomology and Plant Pathology Division of the Indiana Department of Natural Resources (IDNR) also rely on our services.

In 2010, 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 3864 problems (Figure 1) on 2250 samples. We processed 400 additional nursery samples as part of the Cooperative Ag Pest Survey (CAPS) Phytophthora ramorum (Sudden Oak Death) nursery survey in cooperation with the IDNR.

Of the 1532 routine sample submissions to the P&PDL, 1344 were submitted as physical samples, 54 were submitted as digital images accompanied by physical samples and 134 were submitted strictly as electronic submissions of digital images to the P&PDL 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 2). Same day service was provided for 10% of the samples received during 2010 and 60% of the samples were completed in three days or less. A total of 82% of the samples received during 2010 were diagnosed within five working days and 96% of all samples received were answered within 10 working days. An extended turn-around time of greater than 10 days (4% of samples) was documented for those samples requiring more extensive culture work, DNA analysis and other specialized laboratory testing (Figure 3).

Infectious diseases (42%), noninfectious disorders (28%), and arthropod-related problems (17%) were the most common pest categories in 2010 (Figure 4). The most common commodities submitted to the P&PDL were ornamentals (49%) and agronomic crops (18%) (Figure 5). The remaining 33% of samples were distributed among various other commodity groups including turf, vegetables, fruit, specialty crops, and insect, fungal, and aquatic weeds identification.

The Plant and Pest Diagnostic Laboratory (P&PDL) serves as the plant disease diagnostic facility for the Indiana Department of Natural Resources (IDNR). In 2010, P&PDL and IDNR staff worked cooperatively to complete the 2010 National Nursery Survey for Phytophthora ramorum, a disease of regulatory concern. All 400 samples collected from the 22 Indiana nurseries surveyed tested NEGATIVE for the presence of P. ramorum. Further studies on speciation of the Phytophthora spp. isolated from infected tissue are currently being conducted.

In addition, in cooperation with the IDNR and the Indiana Crop Improvement Association (ICIA), the P&PDL also provided disease diagnosis on 118 corn samples as a part of the IDNR's Phytosanitary Certification Program.