Neil Helyer is Fargro's IPM Specialist and with his expert knowledge within the industry, he answers a few questions on the theme of sustainability and Integrated Pest Management solutions.

What are some of the easiest ways for growers to switch to macrobiological controls from pesticides?
For those growers who have not ventured into the biological world, it is worth knowing that this is now the most common form of pest control and is part of UK legislation under the Sustainable Use Directive 2014 that puts IPM as the first line of defence against pests. For most growers it is second nature to use biocontrol, however, it should be remembered that the term should be biological maintenance. Most beneficials are capable of very high degrees of activity but control of a large pest population is likely to take time and undoubtedly leave bodies on the plants; far better to maintain a very low, sub-threshold level of pests than try to control things when all else has failed.  Providing no long persistence, broad-spectrum insecticides have been used you should be able to switch over to biological control quite easily. 

Knowing which beneficials (generic name for biological organisms) to introduce is easier if you know what the target pests are, but this can be made simpler when using polyphagous predators such as lacewing larvae that can feed on most soft-bodied prey.  For aphids, we have individual species of parasitoid wasps that are very effective against their main host species that live on a single host plant such as the Melon & Cotton aphid (Aphis gossypii) on cucumber. For growers with mixed plants, you are likely to have several species of aphids at different times of year.  To manage this situation, we can supply mixes of aphid parasitoids as either 2 species, 3 species, or up to 6 different species of parasitoids in various ratios for different cropping situations.  Whitefly control is similar with several different beneficials; 2 parasitoid wasps that attack the larval stages in different ways and a predatory bug that can feed on all stages, depending on the crop and situation we can advise which biocontrols are most suitable.
 
What are the benefits?
The benefits of using biocontrol are numerous: no residues, no handling/harvest intervals, they can generally be applied within the normal working day (no need to come back when cooler in the summer).  The beneficials are delivered directly from the production facility, although best if introduce ASAP they can be kept for a day or so in a cool, dark place and used within a couple of days.  Once you have seen your first Aphidius mummy (the last stage of a parasitised aphid that contains the parasitoid wasp) you will soon start to find them all over, including outside where they certainly reduce pest numbers that migrate into your production houses.  Conversely, by using fewer pesticides you will start to see more naturally occurring beneficials such as hover-flies and ladybirds, all working on the nursery for free, these are just the ones you can see easily, many other beneficials will give additional control, all for free.
 
How do microbiologically based controls help a grower reduce residues on plants?
There are several microbiological products with UK approval as biopesticides, these are generally applied as a conventional pesticide and as such come under similar legislation. The advantage to these products is the absence of resistance to the active ingredients; providing you can provide the required environmental conditions they should provide high levels of control.  These products usually have zero handling and harvest intervals, most can be integrated with conventional pesticides and with each other. Beneficial nematodes can usually integrate with most other pesticides. There are always a few exceptions, please contact the Fargro Technical Department if in any doubt. 

In what key ways do biological controls differ from conventional chemistry?
Biological control agents are mostly living organisms and as such they need to reproduce, this frequently means they seek out the prey pest organisms in hidden places, including outside the house. Spider mites, for instance, will migrate around the structure of a greenhouse, frequently over-wintering within the actual structure, in places virtually impossible to reach with a spray.  Predatory mites will actively locate spider mites in places on and off plants, giving high degrees of control, they are not affected by day length, and providing temperatures remain above 5 to 8° C they are effective. Other beneficial organisms are equally efficient at the host location and during summer months will be fully effective outside, this effectively reduces the pest population in and around the greenhouses. 

Lacewing larvae can legally be introduced to hedges around and between greenhouses in early spring to prevent pest migration that would normally occur a few weeks later; ideally, this is done when hedges come into new leaf (usually mid-April).  Lacewing larvae (Chrysoperla) are small 6-legged predators of soft-bodied prey including aphids, moth eggs, and young caterpillars, spider mites, and thrips, they can be cannibalistic so a low rate a couple of times is better than a single high number introduction, we suggest a rate of just 10 or so larvae per linear metre of hedges.

What does a standard biological control programme for a grower look like?
Many growers have an on-going biocontrol schedule that runs from year to year, for unheated houses or those with frost protection only, they would start in about week 10 to 12 with parasitoids for aphid control, a few weeks later introduce thrips and whitefly controls, in summer they may introduce spider mite control.  For those growing herbaceous plants they also have to consider vine weevil control.  This is very effective with nematodes as either Nemasys L (‘L’ stands for low-temperature active strain) requiring a minimum soil/compost temperature of 5°C or Exhibitline H / Nemasys H that require a minimum of 12° C for activity and are best used in summer to early autumn. The Fargro technical team has many years of experience in preparing and managing IPM (Integrated Pest Management) programmes, from an initial discussion to running a full biological control schedule.  We can advise on integration with biopesticides and conventional pesticides, along with 30MHz environmental monitoring to determine when pests or diseases are likely and the optimum conditions for biological controls to be most efficient, making Fargro the UK leader in IPM technology.
 
What does the future hold for bios?
With new products on the horizon, the future for biologicals is looking very promising, all the major protected crop growers are using biocontrol and rely on their IPM programme for year-round pest control.  With the loss and restrictions imposed on conventional pesticides we are seeing more biopesticides being introduced to back up macro-biologicals (parasitoids and predators) and in some instances become the main products to control against a wide range of pests. Biological control of several plant diseases is now a reality with specific biofungicides commercially available. AQ10, containing Ampelomyces quisqualis, infects all strains of powdery mildew, having no harvest interval and leaving no residues it is widely used on protected edible crops such as cucumber, herbs, soft fruit, etc.

T34 Biocontrol contains a highly active strain of Trichoderma asperellum with activity against a wide range of damping-off diseases such as Fusarium and Pythium, but also shows good activity against other damping-off diseases as well as triggering the plant's natural defence mechanisms to protect against foliar bacterial and fungal diseases. Taegro is a bacterial preparation containing Bacillus amyloliquefaciens that is applied as a foliar spray to suppress a range of diseases on several edible crops. There are several more biopesticides with UK approvals, and further ones to be introduced in the next few years.

New innovative solutions within the biopesticides market are coming to UK growers, for example, Romeo. Romeo containing cerevisane and is the yeast-derived product that actively triggers the plant's natural defence mechanisms by mimicking a disease attack on the plant. This activates a cell signalling cascade, inducing many defence genes that stimulate phytoalexins (antimicrobial compounds) strengthening cell walls and the leaf cuticle to protect against downy mildew, late blight, and powdery mildew in a range of protected edible crops. Romeo can be used alone or in a tank mix with other fungicides for resistance management or to increase spray performance and it can be used in sustainable organic production. 

In your experience, what have been the biggest driving factors in moving over to biological control?
The great advantage of biological controls is that they usually have zero handling/harvest intervals for all crops and leave no harmful residues. This ticks more boxes for consumers but also creates a better working environment for employees. There will always be pests and diseases that attack or invade crops, managing these in an environmentally friendly way is paramount for the long-term stability of all production systems. Over the years there has been a steady supply of pesticides, some remain in use while the majority have had a relatively short life and been withdrawn. Current trends are looking at protecting the plants from P & D problems with increased monitoring and earlier intervention with cultural and biological controls.