Magazine - NZSTI Disease Laboratory Update

By NZ Sports Field Forum in General News on 24th Nov 2009 21:30

Late last year NZSTI were fortunate to enlist the expertise of retired plant pathologist Dr Mike Christiansen (formerly of AgResearch), who has been working with the Institute establish a disease culturing service. Dr Christiansen’s assistance has enabled the disease laboratory to provide even more accurate disease diagnoses and also to create a collection of NZ turf diseases in culture.

It is hoped that over time the collection can be used to aid in disease identification and also to assess the efficacy of fungicides on the
local strains of disease. Sports fields/stadia The NZSTI disease lab is receiving an increasing number of samples from sports fields and stadiums, especially from council clients. The large land area involved means that the correct identification of diseases prior to fungicide applications is imperative. Errors on such a large scale can be very expensive, notwithstanding the environmental concerns relating to the application of the incorrect fungicide.

This season the main diseases causing problems have been the usual suspects; red thread, melting out and damping off (Pythium sp), however one Auckland client reported a significant problem with an unusual black soot‐like disease on a sportsfield that left a residue on feet etc. The disease was identified as Epicoccum nigrum, which the NZSTI staff has dubbed ‘sooty foot’! This disease is more commonly associated with decomposing material and is possible that excess clippings on the surface had contributed to the abnormally severe outbreak of the disease.



Left: Epicoccum nigrum in the field (Photo: Peter Munro). Right: Epicoccum nigrum spores under magnification (Photo: Brendan Hannan).

DISEASE PREVENTION CHECKLIST
Are you doing everything necessary to prevent summer/ autumn disease?

Cultural
1. Regular light regular feeding (foliar if the grass is stressed or has poor roots) through the summer
months with a sulphate of ammonia‐based fertiliser will help keep stress diseases such red thread at
bay.
2. Ensure that potassium levels are sufficient.
3. Always remove dew from cricket blocks before mowing (or use a Dew Preventer).
4. Keep mowers sharp and properly adjusted.
5. Keep organic matter at a satisfactory level.
6. Water first thing in the morning rather than at night.
7. Avoid topdressing in hot weather or when the grass is under stress. If you are not sure, apply a contact fungicide or avoid topdressing until conditions become more favourable.
8. Avoid deep Verti‐cutting in hot weather.
9. Check that your water is not alkaline as this can encourage some diseases.

Chemical
If you find disease in your turf ensure that you have correctly identified it and know which fungicide is most effective against it.
Contact fungicides (such as Dithane and Thiram) should only be applied prior to mycelial development.
Curative fungicides such as Amistar should only be applied before damage occurs – if you are seeing damage, these chemicals do not work very well. If you are seeing damage you need to ensure that the chemical that you are using is labeled as an ERADICANT fungicide. Examples of eradicants include chlorothalonil, propiconazole and quintozene.

Ensure that you are applying sufficient water in the tank with your fungicide – many turf fungicides require AT LEAST 800L of water/hectare.
Ensure that the water in the tank is not alkaline as this can deactivate some fungicides.

Megan Cushnahan, Regional Manager for Agronomy, NZSTI

Background to the NZ Sports Field Forum
The NZ Sports Field Forum is dedicated to the sharing of information about all aspects of sports field maintenance and administration. The Forum began in Auckland in 1993, when Bruce Paton, a Sports Parks Officer with Auckland City Council called the first gathering of sports field officers from several of the councils in the Auckland Region. The Forum became an Incorporated Society in October 2002, and now has a membership of almost 200 people from throughout NZ, located from Kaitaia to Invercargill. Membership is drawn from contractors, schools, stadiums, consultants, sporting organisations and councils. Membership is free.

Members receive the Forum’s bi-monthly newsletters, news flashes, job vacancies, and invitations to Forum field days, seminars, as well as the New Zealand Turf Conference & Trade Show held every two years.

If you have any questions regarding the Forum, or are interested in becoming a member, please email the newsletter editor, Bobbie-Jo Harvey, on sportsfieldforumnz@gmail.com

Read more articles in General News, by NZ Sports Field Forum or from November 2009.