History 152 Parasites-- Parasitology 94 Parasitology 69 Agronomy 53 India 47 English poetry 39 Parasites 39 Plant Pests, (New March 2000) 32 Poetry 29 Parasitic diseases 28 Agriculture 27 Nematology 27 Politics and government 27 Pest control 26 Plant Breeding and Genetics 26 Plant pests 26 Soil Science and Agricultural Chemistry 26 Natural enemies 23 History India 22 Plant diseases 22 Insects 21 Pathogens, Parasites and Infectious Diseases (Wild Animals), (New March 2000) 21 Plant Physiology 21 Taxonomy 21 English literature 20 Nematoda 20 Parasitism 20 Plant pathology 20 Literature 19 Microbiology 19