Ethanedinitrile (EDN syn cyanogen EDN Fumigas) is a relatively new fumigant with the potential to disinfest quarantine pests from radiata pine (Pinus radiata D Don) logs and sawn timber for export This research evaluated the effects of dose (20 g/m3 or 50 g/m3) timber moisture content (green or kiln dried sawn timber) endgrain sealing (sealed or unsealed timber endgrain) and load factor (11 or 44) on sorption of EDN fumigation chambers Chamber loading significantly influenced sorption with higher loading resulting in greater sorption Changes in the dose of EDN did not affect the sorption pattern Increased moisture content and endgrain sealing both reduced sorption but these effects were relatively small and the differences in sorption patterns caused by moisture content or endgrain sealing decreased over time

In in vitro tests, chitosan at 1, 2, and 4% (w/v) significantly reduced the growth of Sclerotinia sclerotiorum on potato dextrose agar plates. The effect of chitosan coating on sclerotinia rot of carrots (Daucus carota L.) held at 22°C was also investigated. Carrot roots were coated with chitosan solutions (2 or 4%) and inoculated with mycelial plugs of S. sclerotiorum culture. After 5 days of storage, chitosan at both rates reduced significantly the incidence of rot (from 88 to c. 28%) and also the lesion size (from 26 to c. 12 mm) of the rot on roots. Microscope studies revealed that fungal mycelium exposed to chitosan appeared to be deformed and dead, whereas untreated mycelium was normal in appearance.

Ethanedinitrile (EDN) has been identified as a possible alternative fumigant to methyl bromide (MB) as a phytosanitary treatment for New Zealand export logs A review of MB phytosanitary schedules has indicated that the treatment rates used in New Zealand may be able to be significantly reduced The toxicity of EDN was compared in the laboratory to that of reduced rates of MB using different life stages of the burnt pine longhorn beetle Arhopalus ferus Naked insects were fumigated with MB at 10C and 20C for 4 h or with EDN at the same temperatures for 3 h The mortalities achieved and the CT products calculated indicate that (1) a reduction in MB usage may be possible for the treatment of logs exported from New Zealand and that (2) EDN has potential as a phytosanitary alternative to MB for the treatment of logs

Twenty-five isolates of Trichoderma spp. were screened against clubroot (Plasmodiophora brassicae) on Chinese cabbage (Brassica chinensis L.)'Wong-Bok' in a glasshouse experiment. Seventeen of the 25 isolates tested significantly reduced disease severity compared to the untreated control. In a subsequent pot trial test with 10 of these isolates, nine significantly increased the top weight of the plant. Field trial results with two isolates (TC45 and TC64) and chitosan (crab shell extract) gave significant reduction of club weight on roots but did not increase the top weights of the plant. Benomyl soil drench was also effective in disease control and significantly increased top weight. No phytotoxicity was observed on any of the treatments tested.

In laboratory tests, germination of conidia on glass slides of Sphaerotheca fuliginea was greatest at 25°C in high humidity, although the germination rate was generally low. No germination was observed below 15°C or above 30°C, or at relative humidity below 94%. Field studies of the development of powdery mildew on squash plants showed that symptoms first appeared on old leaves. Symptoms did not appear on first leaves until 7-8 weeks after emergence, but appeared progressively earlier on late formed leaves (2 weeks). Only a small proportion of the conidia germinated when placed on young leaves (2 weeks), but many germinated on older leaves (6 weeks). A field experiment indicated that the first symptoms of powdery mildew appeared approximately 1 week after a prolonged period of continuous leaf wetness (about 12 h) and high humidity (about 95%) in the summer when temperatures frequently rose above 22°C. The disease begins in isolated patches on leaves in dense canopies more than on exposed leaves.