If you told the bloke sitting next to you in the pub that you spread mustard on the land and then dug it in, he would probably summon the men in white coats with the straitjacket and have you carted off right there and then.

But this is actually something that farmers have done for centuries and something that our generation is rediscovering now.

Primarily used as a green manure, Caliente Mustard is also said to have excellent properties as a bio-fumigant.

Stephen Ball is the fieldsman for Hazeldene and has been working with Hazeldene growers in Lancashire to evaluate bio-fumigants and companion plants in the fight against weeds, bugs, beasties and diseases.

“So far, we have put in a couple of sowings of Caliente and we are in the middle of assessing how helpful it is going to be,” he says. “We grew it to about shoulder height, to its flowering stage, chopped it up finely and then incorporated it as quick as we could afterwards. If it works well as a bio-fumigant, the big prize for us will be control of weeds and Sclerotinia.”

Weeds in the baby leaf beds are a nightmare in terms of contamination of product in the factory and Sclerotinia, especially in a wet summer, destroys thousands of lettuce heads. The disease is uncompromising. It simply melts the lettuce, just like an ice cream left out in the sun.

The current methods of seedbed preparation often involve the use of synthesized chemicals that fumigate the land - so if we can make this natural mustard product work for us, it is a great leap forward.

The green manure approach, as part of a sound rotational strategy, is one of the key factors for soil improvement.

There are downsides, though. It is clear that you have to chop it up and incorporate it at the right time. Leave it too late and it is not only less effective at bio-fumigation, but the trash being put back in makes new sowings of baby leaf very tricky. It may also promote slug populations in certain conditions, as well as perhaps increasing levels of club root.

As with all things, it’s a balance. A healthier soil will grow a healthier plant that is more able to survive pest and disease attacks. If we also see our weed levels drop, especially with Propachlor unlikely to be available to lettuce growers next season, and Sclerotinia becomes a thing of the past, we will consider it a major success.

Whatever else we may conclude about Phacelia, everyone agrees that it looks very pretty when planted out as a companion plant. Phacelia is an easy plant to grow, producing a blue flower that has the most ingenious properties of attracting many of the insects that we need to help us.

When it is in flower, the beds of Phacelia are literally humming with insects such as hoverflies, as well as ladybirds and lacewings. All of these friendly bugs, at some point in their life cycle, eat the nasties that infest our crops, especially aphids.

The most stunning attribute of Phacelia is as an attractant to bees, as the blue flowers are literally heaving with them.

If you have a crop that needs pollinating, put a measured amount of Phacelia in or around the crop and you will attract every bee in the district! Take care though. Too much Phacelia and the bees will never leave the Phacelia to go into your crop.

But does it help with pest control in the crop? Our findings are clear. In the areas adjacent to the beds of Phacelia, we can actually see much higher levels of ladybirds and hoverflies in the crop and very few aphids.

The downside - and there is always a downside - is that when we come to harvest the crop, our friendly bugs are still there. So the customer still rejects the product because it has bugs in it. We can just about put the sprayer back in the shed because the ladybirds ate the aphids, but then the customer doesn’t actually want the ladybirds either... another little paradox for us to conjure with.

Next time we will look at how breeding resistance into crops such as spinach and lettuce could be a highly effective method in a reduced pesticide-cropping programme.

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