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United States Department of Agriculture

Agricultural Research Service

Research Gaps
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Return to top Expertise

Among the ARS Beltsville laboratories with systematics expertise, the number of research positions in systematics has varied over the past ten years. There has been a substantial decline in the number of positions in the Systematic Entomology Laboratory and among vascular plant taxonomists. The number of research scientists in systematics at SEL reached a maximum of 29 positions in the mid 1980's and is at a low today of 17 positions with the potential to continue the decline due to retirements in the next few years. The number of systematics positions in mycology (4), nematology (2) and parasitology (3) in the SBML, NL and PBESL, respectively, is small and has declined by two positions in each discipline over the past ten years. In addition the SBML has lost two systematics positions in vascular plants with one research and one service scientist position remaining. Given the decline in systematics expertise in these organisms of importance to agriculture, it seems imperative that the government, specifically ARS, take on the responsibility of maintaining systematics expertise for agriculture as a federal responsibility.

The gaps in expertise for groups of organisms of importance to agriculture are considerable especially when viewed from an ARS perspective but unfortunately the same situation exists globally. In fact, the U.S. federal government, specifically Beltsville Area ARS laboratories, are fast becoming global centers of systematics expertise. Some of the most critical areas where we need new or expanded coverage include those below. These do not include research areas where we have scientists who are eligible to retire (e.g. scale insects):

Return to top Mycology

Fungi are an enormous group of organisms second only to insects in the numbers of species. Yet, globally there are very few systematic mycologists. With the demise of the International Mycological Institute in CABI and the decline in systematics in Canada, the SBML with four scientists may be the largest group of systematic mycologists in North America and Europe. There are several major groups of fungi that are extremely important to agriculture and biosecurity for which little systematics expertise exists. In order to serve the needs of agriculture, research scientist positions for these groups of fungi are requested.

Downy mildews - The Peronosporales and Sclerosporales or downy mildews (Oomycetes) are a group of obligate parasitic fungi that cause serious diseases of crop plants. A number of these fungal species particularly those affecting corn, sorghum and sugarcane do not occur in North America and would be devastating if introduced either accidentally or otherwise. This group includes three of the ten organisms on the APHIS list of biosecurity select agents.

Anthracnose fungi - Fungi that cause anthracnose diseases belong to a very large group referred to as coelomycetes. These include the megagenus Colletotrichum that attacks almost every crop for which systematics knowledge is extremely limited. Previously based entirely on morphological characters, recent molecular work on strains from just one host (strawberry) suggest that the taxonomy is in dire need of reevaluation. These fungi are very commonly encountered on agricultural commodities at ports of entry.

Phytophthora and other blight fungi - Late blight of potatoes is the most famous member of the genus Phytophthora (Oomycetes) but many additional species exist that are potentially devastating plant pathogens. A new disease in the western United States known as sudden oak death (SOD) is caused by an apparently introduced species of Phytophthora. Understanding the SOD syndrome has been complicated by the lack of data on host specificity of the causal organism.

Powdery mildews - The Erysiphales or powdery mildews (Ascomycetes) are a group of obligate parasitic fungi that cause diseases of numerous crop and horticultural plants. This group of fungi has become more prominent and invasive in recent years especially on greenhouse-grown plants such as tomato powdery mildew and poinsettia powdery mildew, both of great concern to growers. Many powdery mildews are host-specific while a few species are considered generalists, although experiments supporting these assumptions have not been performed. Recent molecular results suggest that traditional concepts of genera and species in the powdery mildews are erroneous. Comprehensive studies of the powdery mildews are needed to evaluated the generic and species concepts and determine their host specificity.

Morphology of rust fungi - The Uredinales or rust fungi are a large group of fungi including about 20,000 species. Funding was received for a new scientist to study of the molecular systematics of rust fungi. The rusts are an especially difficult group of fungi to study because they are obligate pathogens that cannot be grown in culture. The technical difficulties of studying the molecular systematics of these fungi to be especially difficult, yet, molecular work is urgently needed to understand the systematics of these fungi. A second, complementary position would be desirable to study the micromorphology of rust fungi, including the development of an on-line, interactive system for the identification of rust fungi.

Return to top Parasitology

Tissue Cyst Forming Coccidia - These organisms include Toxoplasma, Neospora, Sarcocystis, recognized as real or potential zoonotic parasites and significant pathogens in the human and animal food chains. Toxoplasma gondii is a ubiquitous food borne organism that constitutes a major threat to public health as an opportunistic parasite occurring in up to half the global human population; costs for human toxoplasmosis in the US alone are $400 million annually. Neospora caninum is a recently recognized coccidian that is now regarded as the major cause of bovine abortion in the North America. A BARC scientist near retirement is the recognized world authority on comparative morphology and ultrastructure of these organisms; global resources for diagnostics are otherwise limited.

Gastrointestinal Nematodes in Ruminants - Nematode parasites in food animals including cattle and sheep are the source of over $2 billion in losses annually in the United States. Efforts to understand epidemiology, distribution and disease and the most efficacious basis for control have often been hampered by difficulties in the identification of these parasites and pathogens. Systematics knowledge also contributes to proactive programs for identification of exotic, introduced, invasive or emergent parasites in North American food animals. Remaining expertise in North America for critical systematics research on the trichostrongyloid nematodes based on comparative morphology is now limited to 2 SY's at the USNPC with one scientist near retirement. Capacity for a molecular program is not available.

Return to top Entomology

Whiteflies - These tiny insects can be incredibly devastating crop pests. In a single year the sweet potato whitefly (Bemisia) caused damage estimated at $600 million dollars. In addition, there are numerous species of whiteflies with a high potential to invade the U.S. The SEL has been without a whitefly expert for over half a decade.

Braconid parasitic wasps - Parasitic wasps are the primary group of organisms used in biological control of pest insects. The family Braconidae has provided many species which have been successful biocontrol agents against a variety of plant feeding pests. SEL has been without an expert on braconids since 1993.

Weevils - One of the largest and most damaging groups of insect pests, the weevils cause hundreds of millions of dollars of losses each year. A mega-diverse group with tens of thousands of species, the weevils are currently covered on a part-time basis by a researcher who also has responsibility for the longhorned beetles (Cerambycidae).

Plant feeding Diptera - Several families of true flies feed on plants. Among these, the Agromyzidae are the most poorly known and most damaging. While we have an active molecular program with a focus on some agromyzid taxa we are badly in need of additional research on this group.

Lepidopteran larvae - While the three researchers currently employed to investigate moths all have some responsibility for work on immature stages, a position whose principle thrust would focus on larvae and larval character systems would be of great benefit to our customers, especially APHIS/PPQ.

True Bugs - Among the most often intercepted groups at ports, the true bugs contain both pests and beneficials. At the present time a single scientists cover the entire suborder Heteroptera.

Insect molecular systematics - Our single molecular systematics position focuses on leafmining Diptera, but also collaborates with scientists on projects across several insect orders. An expansion of our molecular program would allow us to branch out into another taxon.

Return to top Nematology

Insect Parasitic nematodes - Controlling insects through the use of parasitic nematodes holds great potential to reduce costs to farmers and benefit the environment.

Infraspecific and molecular systematics - Many of the problems in using nematodes can be attributed to our inability to sort out problems below the species level. This position would be very helpful.

Last Modified: 9/15/2006
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