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Two sister-samples of 400 tubers each were taken from seed potato lots of cultivars Atlantic, Hampton, and Russet Norkotah, all of which were grown in New York State during the summer of 1996. One sample of each cultivar was planted in Homestead, Florida in a winter test plot where plants were inspected for disease symptoms. Tubers in the other sample were directly tested for the presence of potato potyvirus Y (PVY) and potato leafroll luteovirus (PLRV) using reverse transcription polymerase chain reaction (RT-PCR) methods. Hampton tubers appeared to have similar PVY infection rates in dormant tubers according to summer inspection, Florida winter inspection and RT-PCR, whereas Florida testing appeared to reveal a higher PVY infection rate in Atlantic tubers compared to RT-PCR and summer inspection. In contrast, higher rates of PVY infection in Russet Norkotah were observed by RT-PCR compared to Florida tests. In addition, RT-PCR appeared to detect PLRV at higher rates in all three cultivars compared to Florida test results. All tubers positive for virus by RT-PCR were sprouted in a greenhouse and ELISA results from leaves corroborated the PCR results in 85% of the positive cases, and 100% of the negative cases that were sprouted.

Two acid rain experiments were conducted, one at Oulu using transplanted seedlings of Picea abies and Pinus sylvestris, and the other with adult pines at Kevo where test plots were designated in a natural mixed stand of Pinus sylvestris and Betula tortuosa. The acid solution was made by adding H2SO4 and HNO3 (vol:vol 2:1, pH adjusted to 3 and 4) to clean water. The Oulu experiment was carried out from 1986 to 1989, and Kevo from 1985 to 1989. No visible injuries related directly to the acid ram treatment could be observed after 3 yr of the experiments, but microscopic examination revealed significant changes in the structure and morphology of the needles. The conifer seedlings treated at pH 3 had significant amounts of scattered CaSO4 crystallites and characteristic piles and bows on the needle surfaces, as detected with EDS. The number of CaSO4 crystallites was higher on the surfaces of the spruce needles than those of the pine needles. The current needles had more crystallites than the previous year’s needles.

Field and greenhouse readings in Maine together with test plot readings in Florida showed the incidence of potato leafroll virus infection in 10 Kennebec seed lots from south, central and northern Aroostook County to be about 1.2%. When the seed lots were indexed by aphid transmission of the virus toPhysalis floridana Rydb. in January and July the incidence of leafroll was found to be 2% and 10% respectively. SinceP. floridana detects mild strains as well as those capable of causing visible symptoms on potato, these results indicate that mild strains are present in the Kennebec variety being grown for seed in Aroostook County. The authors indicate, however, that leafroll symptom expression inP. floridana, in many instances, was not definitive and they suggest that their data may reflect an inaccurate estimate of the prevalence of mild strains of leafroll in Maine.

1. Trials were carried out with six different fungicides, namelyCoppesan, Copper Sandoz, Copravit, Shell copper, Perenox andDithane for the control of late blight of potatoes in high rainfall areas in the hills of West Bengal. 2. The fungicides were applied at five different concentrations namely, 1,25–2,50–3,00–4,00 and 5,00 lbs in 100 gallons of water at four different intervals (14, 10, 8 and 6 days respectively). Under severe late blight conditions in the hills the disease was succesfully controlled until 136 days after planting in all test plots with different fungicides when sprayed at an interval of 8 and 6 days. The “Optimum spray interval” was found to be 8 days since there was no appreciable difference in the incidence of infection between plots sprayed at 8-and 6-days’ intervals. 3. The effect due to different fungicides, different concentrations, different intervals between spray applications and the interaction between fungicides and interval between spray applications were all significant at the 1 percent level. 4. Concentrations of fungicide had the most pronounced effect on yield. Progressive increase in concentrations of fungicides gave progressive increase in yield. 5. Shorter intervals between spray applications gave more succesful control of late blight infections on foliage. 6. Highest average yields were obtained by usingCopravit andCoppesan which gave only significantly higher yields overShell copper at 5 percent level. No significant difference in yield was noticed amongst the effect of other fungicides viz.,Copravit, Coppesan, Perenox andDithane.

The three new potato varieties, Sebago, Sequoia and Pontiac which have proved to be more resistant to freezing injury in the early stages of growth and more drought resistant than eleven other varieties, have produced the best yields in test plots at Hastings, Florida, during the past 7 years. Sebago and Pontiac yielded about one-third more U. S. No. I tubers per acre than Katahdin whereas Sequoia exceeded the yield of the latter by 50 per cent. Within the past 7 years, Sebago and Katahdin have supplanted the old standard variety, Spaulding Rose, and have become the leading varieties at Hastings. During the past season 65 per cent of the acreage was planted to Sebago and 28 per cent to Katahdin. Pontiac probably will never be grown very extensively in the Hastings Section since white-skinned varieties have always been the leading ones grown there, and markets have been developed for Hastings-grown potatoes of that color. However, Pontiac may replace Bliss Triumph and become a leading red variety in other potato-growing sections of the state. The color, shape and uniformity of the tubers of any variety generally determine its salability. If the Sequoia is not discriminated against because of the russet patches on the skin of the tubers and the slight variations in the shape of the tubers, it should soon become the leading variety at Hastings because of its superior yielding ability.

1. Selection of individual plants in seedling families in the scab test plot was relatively ineffective in isolating scab resistant seedlings. 2. Consistent ratings for mean scab index were obtained by growing four hills of a clone in a heavily infected scab test plot. 3. Crosses between parents of the same clonal resistance resulted in progenies which differed widely in the percentage of resistant seedlings. 4. Crosses between parents derived from the same resistant ancestor seemed to produce progeny of slightly lower resistance than where the two parents had different resistant ancestry. 5. A test of 399 selections from 30 crosses showed that when both parents had a scab index of 3 or less, from 11 to 37 per cent of the selections had an index of 2 or less, and from 43 to 63 per cent an index of 3 or less.

KIE: As a result of a threatened suit by Jeremy Rifkin, Stanford University has postponed an experiment involving a test plot of genetically-engineered corn. At issue is an injunction forbidding the Recombinant DNA Advisory Committee of the National Institutes of Health from approving federal funding of experiments entailing the release of recombinant DNA into the environment. Rifkin's legal argument is that an environmnental impact statement must be filed for both commercially- and federally-funded research. It is expected that Rifkin's demand for equal treatment regardless of funding source will be agreed to by NIH.