Celery Crops Research Articles

Susceptibility of Celery Cultivars to Leaf Curl Caused by Colletotrichum Acutatum.

Leaf curl caused by Colletotrichum acutatum was responsible for severe yield losses in celery crops grown in southeast Queensland in the summer of 1990. This led to a study of the susceptibility of cultivars. The standard cultivars American Stringless, Toowoomba Early Green, and Greengiant were more resistant than the new cultivars Bishop and H122.

Soil metabolism of the herbicide chlorbromuron in rape celery crops

In a 2-year study, the herbicide chlorbromuron was applied to the soil of rape celery crops grown in greenhouses (glass, polyethylene or polycarbonate) or in the field (with or without plastic sheet) in two regions with different soil types. Chlorbromuron and 4-bromo-3-chloraniline were measured in the soils. The half-life of chlorbromuron in soil was 55–66 days in the greenhouses, and 30–43 days in the field. 4-Bromo-3-chloraniline was generated by microbial and enzymatic processes; its concentration at harvest in soil was 500 ng g −1 dry soil. At harvest, in the bulb of the rape celery, the concentrations of chlorbromuron and of 4-bromo-3-chloraniline were equal or lower than 20 ng g −1weight. The herbicide efficience is discussed in relationship to chlorbromuron soil concentrations.

Is celery yellow net c used by parsnip yellow fleck virus

Celery yellow net w s described by Hollings (1964) s severe dise se of celery (Apium graveolens L. var. duke (Miller) DC.) that could be transmitted by grafting nd occasionally by mechanical inocul tion with leaf extracts. Pemberton & Frost (1986) observed similar symptoms in celery crops. but were unable to isolate the causal agent.During recent attempts to isolate the causal gent of celery yellow‐spot, another disease previously reported by Hollings (1964) and Pemberton & Frost (1986), we found that two of our samples from crop in Cheshire contained different virus. As well as yellow spots, these two plants also had yellow‐net symptoms on the older leaves, and one of the plants was stunted with some distortion of the young leaflets. The two virus isolates appeared identical from extensive testing on range of herbaceous indicator plants, so one of them, CV506, w s selected for further study

Celery Mosaic Virus in England

SUMMARYA virus has been isolated from celery crops in Lincolnshire, Cambridgeshire, and Norfolk, from eight different cultivars on 15 of 18 farms sampled, but has not been found in any cultivars on 10 farms in Lancashire. It has also been isolated from hemlock on three farms in Cambridgeshire. The incidence of infection has varied considerably with an average level of about 15 per cent but 90 per cent crop infections have been observed.The virus causes most prominent symptoms in cvs. Lathom Blanching and Fenlander, causing a slight stunting of the former and a more serious reduction in growth of the latter. It is aphid‐transmitted in a non‐persistent manner. The virus has flexuous rod‐shaped particles approximately 780 nm in length, and is apparently restricted in its host range to the Umbelliferae. Its relationship to Western celery mosaic virus */*: */*: E/E: S/Ap is discussed.

Optimal Irrigation Quantity and Frequency

Mathematical models are derived for two different irrigation practices: (1) Soil moisture is kept equal or below the optimal soil moisture and (2) soil moisture is allowed to fluctuate above or below the optimal soil moisture. Evaluation of models indicated that the optimal irrigation quantity and frequency can be determined when irrigation costs and average consumptive use are known. The major irrigation cost consists of expense and economic losses. The former is the cost of purchasing and delivering water to the farm and the latter is the loss caused by crops grown under unfavorable soil moisture conditions. The optimal soil moisture, optimal yield and cost functions are obtained from irrigation experiments. Two examples are presented for lettuce and celery crops in Hawaii. The developed technique can be used for other crops if similar information is available. This study showed that the general irrigation practice, irrigating to the field capacity, is not always the optimal irrigation schedule.

Some Properties of Five Viruses of Celery (Apium GraveolensL.) in Britain

The symptoms and some properties of five viruses isolated from celery crops in Britain are described. Cucumber mosaic and lucerne mosaic viruses were found to be prevalent in celery and other crops. Tomato aspermy virus, though widespread in chrysanthemum and occasional in tomato crops in England, and economically damaging in Continental celery crops, has not so far been reported in celery in Britain. British celery varieties tested were resistant to experimental infection with tomato aspermy virus. These three viruses were readily isolated, purified and identified.Three viruses, designated celery yellow spot, celery yellow vein and celery ringspot, isolated from affected celery plants, were less readily transmitted from celery to celery, and could not be purified by techniques that succeed with many viruses.Celery yellow spot was transmitted by sap-rubbing inoculation only when cucumber mosaic virus was also present ; it was tentatively identified with the celery yellow spot virus reported from the U.S.A. Celery ringspot virus showed some similarities to the poison hemlock ringspot virus found in the U.S.A., but none of the critical tests for virus identification could be applied to either of these two viruses. Celery yellow net virus differed from all the viruses so far recorded in celery. The chronic symptoms of the different viruses in celery were often similar, and therefore unreliable for diagnosis. The initial or “ shock ” symptoms, however, were usually distinctive.