Financial support was provided through Department of Agriculture Cooperative Agreement 12-14-7001-518. We thank Johnny Enfinger for assistance with the sampling of ponds and Jan Fowler for technical assistance with the laboratory assays. We thank J. T. Ratcliffe for help in selecting certain ponds that were sampled. We also thank E. E. Butler for identification of the Sclerotium isolate.

No abstract

A rifampicin-nalidixic acid mutant of Pseudomonas viridiflava (PV) was studied in the field and greenhouse with respect to its epiphytic survival on the roots and foliage of a susceptible (FM 6203) and resistant (Ontario 7710) tomato cultivar and 16 weed species. In the field, populations varied between years, which was attributed to differences in environmental conditions. Hot, dry conditions caused rapid decline or elimination of populations. Some hosts were more conducive than others in promoting epiphytic growth, and generally, roots were better survival sites than foliage. Some hosts such as johnsongrass, lambsquarters, pigweed, prickly sida, and red sorrel had no detectable populations of PV on foliage 2 weeks after inoculation. (Plants had been misted with a 10(8) cfu/ml suspension until run off occurred.) PV was recovered at week 4 on the foliage of the two tomato cultivars, beggarweed, jimsonweed, morning glory, smooth vetch, and wild mustard, and was recovered until week 16 on roots of buckhorn plantain in the field and for the same period on the ground cherry in the field and greenhouse. In scanning electron microscopy studies, PV was observed to survive as microcolonies in depressions between epidermal cells, around trichomes, along veins, and sometimes around stomates of tomato and beggarweed. Bacterial cells sometimes were held together and to the leaf surface by fibril-like strands. These studies show that PV does have an epiphytic stage on both tomato and certain weed species. However, the epidemiological significance of the epiphytic stage is probably dependent on environmental conditions.

No abstract

The transplant industry in southern Georgia began in 1908 when a few growers in the Tifton area started to produce field-grown plants for sale to home gardeners and producers in more northern areas (I). Attempts to mtabish the industry on a commercial scale began in 1914 when an Indiana tomato packing company arranged with several Tifton area growers to plant 77 1 kg of seed for