{"id":6593,"date":"2013-01-18T00:00:00","date_gmt":"2013-01-17T11:00:00","guid":{"rendered":"https:\/\/www.farmersweekly.co.nz\/organic-solution-to-tpp\/"},"modified":"2013-01-18T00:00:00","modified_gmt":"2013-01-17T11:00:00","slug":"organic-solution-to-tpp","status":"publish","type":"post","link":"https:\/\/www.farmersweekly.co.nz\/news\/organic-solution-to-tpp\/","title":{"rendered":"Organic solution to TPP"},"content":{"rendered":"Reading Time: <\/span> 3<\/span> minutes<\/span><\/span>

Dr Charles Merfield runs the 14-month-old Future Farming Centre, an outfit funded by a charitable trust that has a practical, organic-centred approach to agriculture.<\/p>\n

When it comes to the tomato and potato pest known widely as TPP, Merfield has a bright, white example of how the organic method can pay for itself.<\/p>\n

Many growers have spent heavily on agri-chemicals since TPP was discovered in Auckland in 2006, having arrived from the United States.<\/p>\n

In the North Island it is wiping out crops and has caused a huge increase in pesticide use, Merfield says.<\/p>\n

He says large organic growers have been tied in knots by the pest and life hasn\u2019t been much brighter for the \u201cconventional guys\u201d, who are dealing with chemical resistance.<\/p>\n

That is why Merfield is excited about plastic insect-mesh crop covers laid out in the north-west corner of Lincoln\u2019s campus.<\/p>\n

Last year he did a \u201cvery quick and dirty trial\u201d using glasshouse quarantine mesh, throwing some of it over a field of potatoes.<\/p>\n

It kept the psyllid numbers down dramatically, even if the most determined still managed to slip under the material.<\/p>\n

\u201cBut we also got a dramatic reduction in potato blight, which was the real eye-opener. You\u2019d kind of expect the covers to work \u2013 it\u2019s pretty straightforward stuff \u2013 but the big concern was that if you have high humidity underneath you\u2019ll have lots of potato blight. We got completely the opposite.\u201d<\/p>\n

This result encouraged Merfield and a small band of helpers to apply a purpose-built mesh cover from Europe.<\/p>\n

It is a form of mono-filament, polypropylene plastic, which Merfield likens to thin, woven fishing line.<\/p>\n

\u201cIf we have a similar result this year we should have very low numbers of psyllid underneath the potatoes and hopefully we\u2019ll see the same result in the blight,\u201d he said.<\/p>\n

Sticky traps will record the insect invasion, spore traps will register blight and data loggers will measure temperature.<\/p>\n

\u201cIf this pans out, we could have not only a non-chemical solution for psyllid on field crops but if we\u2019re also getting a significant blight result this could be quite important globally,\u201d he said.<\/p>\n

For example, he said, in India and wider parts of Asia there are major problems with potato tuber moth. If the Lincoln trials could be replicated around New Zealand and then overseas the mesh covers could be a perfect non-chemical control for the month \u2013 and deal to blight as well.<\/p>\n

\u201cSo there could be the start of a whole new way of managing blight, by actually putting covers over crops and looking at what the causal effect is.\u201d<\/p>\n

It might be light at play, Merfield said, but he admitted he had no idea. The next step would be repeating the trial at up to eight sites around NZ.<\/p>\n

In terms of cost, he knows the mesh lasts about 10 years and you could probably spend about $10,000\/ha on it.<\/p>\n

\u201cSo that\u2019s about $1000\/year. Some of the conventional growers are spending more than that on the insecticides.\u201d<\/p>\n

All said it was not cheap and in some senses would be a \u201cpain in the butt\u201d to set up and maintain, he conceded.<\/p>\n

But he hopes that even the most blighted growers will try the mesh treatment, especially seed potato specialists, who are also worried about aphid-vector viruses.<\/p>\n

His believes the mesh can stop aphids, psyllid and possibly blight in form of a three-in-one insurance policy. Ideally it would be a case of \u201cput this on, you walk away and shut the gate.\u201d<\/p>\n

\u201cYou just swallow the aggro. You say \u2018I\u2019m going to make another $300\/ha by using sheet rather than chemicals and I\u2019m not going to have resistance problems \u2013 my market\u2019s going to be happier\u2019. You go, just get the gear, get the labour organised and get on with it.<\/p>\n

\u201cYou can just imagine there\u2019s stakes here and some poor sod has got to go round and pull it. If you\u2019re doing it on a field you\u2019d have a sheet 100 metres long, just going over the entire field and you\u2019d mechanise it with bits and pieces. So it\u2019s not an easy solution but if it\u2019s your only solution and it\u2019s cheaper than a chemical solution\u2026I\u2019ve found very few growers and farmers who don\u2019t understand \u2018cheaper\u2019.\u201d<\/p>\n

Merfield suspects organic potato farmers who have previously had to walk away from the game because of the psyllid might now be able to plant again on their own terms, giving retailers an adjusted price that compensates for mesh over the crop.<\/p>\n

\u201cIt would be a rather rosy, warm feeling to ring up the supermarket and tell them what the price is going to be,\u201d he says.<\/p>\n

Related story:<\/strong> Insect nets may be useful in NZ<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"If you\u2019re prepared to \u201cswallow the aggro\u201d, a pokey little plot at Lincoln University hints at world-leading relief for tomato and potato growers ravaged by combinations of psyllid, blight and aphid.\n","protected":false},"author":33,"featured_media":6594,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_FSMCFIC_featured_image_caption":"","_FSMCFIC_featured_image_nocaption":"","_FSMCFIC_featured_image_hide":"","footnotes":""},"categories":[3],"tags":[],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t