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Simon Cook’s Nuffield Thoughts: Part 6

As the rest of the group I had been travelling for 6 weeks with departed, I stayed in Alabama to begin the next phase of my Nuffield experience. The third and final component of our program is a further 10 -12 weeks travelling on our own researching a subject of particular interest. In my case given the impact of PSA to our industry and my ongoing involvement with the kiwifruit industries biosecurity body KVH, it was only natural that my research topic would focus on biosecurity.

My first stop was near Auburn in Alabama where a large kiwifruit orchard is being developed. The orchard is a 200 acre trial to see if kiwifruit can successfully be grown in the area. The person running the site, Clint Wall, will be known to many here as he spent time working for Seeka in a technical role based in Te Puke before spending some time working for them up the Coromandel Peninsular. One of Clint’s major challenges is dealing with Brown Marmorated Stink Bug (BMSB).

Clint has been using a number of the techniques that we had been discussing locally as possible management plans if we have an incursion. One of the main techniques discussed was the use of bait plants to lure BMSB out of the kiwifruit so we can then use more toxic sprays that would cause residue problems. Unfortunately Clint’s experience is that this is not successful as the bugs prefer to stay in the kiwifruit. As I was leaving, his next plan was the use of chemical impregnated cloth with bright lights shining on it at night to try and attract BMSB. This was being trialed with limited success elsewhere, however there is significant risk of off target deaths. Unfortunately desperation can lead to less than ideal methods. So far the most successful method has been the use of baited traps that are regularly capturing hundreds of bugs.

It is interesting to note in Alabama, trissolcus japonicus the Samurai Wasp is not present. When I got to Pennsylvania later in my trip I found the populations of BMSB that had initially exploded in that area were now heavily reduced and BMSB was not considered as significant as it had been. A large factor in the reduction of the population was being accredited to the presence of the Samurai Wasp. This is great news given that the EPA in New Zealand has recently given approval for the introduction of the wasp in the event of a BMSB population being discovered in NZ.

In China BMSB is not a major problem because the Samurai wasp has developed as a natural control to keep its numbers in check. When BMSB is moved to a new environment with no natural predator or natural control, then there is nothing to stop its numbers expanding to plague proportions. This is the real risk with biosecurity incursions where you can get the pest without its corresponding biocontrol and a pest which at home can seem rather benign, can suddenly explode in numbers and cause major problems to industry. This can also cause problems identifying what our real threats are in terms of invasive species, as in their home countries they’re quite often are not an issue. In China Yellow Spotted Sting Bug (YSSB) has more of an impact on agriculture than BMSB.

After leaving Auburn and Alabama, I drove down to look at Citrus Greening or HLB in Florida. Citrus Greening disease has its origins in China where it is known as Huanglongbing (HLB) which literally translates to yellow dragon disease. The story of HLB in Florida actually starts prior to its arrival. Before HLB, Florida suffered an incursion of citrus canker. One of the initial responses to control canker was a cut out program that resulted in taking out a circle of 1900ft around any infected plant. Unfortunately despite cutting out a large area of orchard, a hurricane swept through Florida that year spreading the wind and rain born disease everywhere. The complete failure of the cutout program completely undermined the notion of ever using this technique to control future incursions.

The first sign of a coming problem with HLB was the arrival of the Asian citrus psyllid. The psyllid was a well known vector for the transmission of the disease. For 4 years they battled the psyllid incursion without success keeping a close eye out for the first sign of HLB. The psyllid itself does very little damage, and after 4 years with no sign of HLB growers started to become complacent towards the management of the psyllid, which is very difficult to control. This all changed with the first positive identification of HLB in an orchard in Florida. Interestingly talking with a grapefruit grower, this still did not concern them as they mistakenly believed it would not affect them. The industry instead has been devastated with total production dropping from 140m boxes to currently only 6m boxes. The number of post harvest facilities has similarly dropped from in the 80’s to now less than 10. This represents a catastrophic reduction in income and jobs within the local community. The overall citrus industry has dropped from 9 billion to 4.5 billion.

Since the incursion around $250m USD has been invested in research to try and overcome the incursion with little success. Whilst waiting for some solution, growers find themselves very much in survival mode and unsure of their future. Many growers have been forced to abandon orchards or cut them out and look at trying to grow some other crop instead of citrus. I saw a number of orchards that once produced citrus now growing blueberries, watermelon, onions, basically trying anything they can think of to survive. What does the future hold? The most likely solution to allow the industry to survive will be the breeding of new tolerant varieties, most likely created using some kind of genetic modification. Without the use of GM it is unlikely a new tolerant variety will be bred anytime soon. Natural selection breeding typically takes around 20 years to deliver new solutions – I’m not sure the industry can wait that long.

This does bring to mind the recent success in Hawkes Bay where farmers have been fighting to not allow any form of GM crop to be grown there. After 3 years of fighting this Federated Farmers have recently announced that they are going to discontinue fighting for the availability of GM. Whilst I understand why the local farmers and growers have been fighting to be GM free with all the pressure being exerted in our major EU markets, I cant help thinking this decision may be short sighted and potentially expose them to greater risk at some time in the future.

When I look at what PSA did to the kiwifruit industry, the only reason we survived and were able to rebuild so quickly was the fact we had an alternative variety that had some inherent resistance to PSA. This resistance was however, sheer luck as it was never a consideration in the breeding program. If G3 did not have any tolerance to PSA then I shudder to think what our industry would look like now. Would our industry have been able to survive long enough to breed a tolerant gold variety and how hard would the kiwifruit industry have looked at gene editing technology in order to save our industry.

We are all exposed to the risk of new pests and disease and never know when we might be hit next. Increasing international travel and trade only increases the likelihood of these incursions and by ruling out one of the solutions that probably has the greatest chance of long term success, are we potentially shooting ourselves in the foot? If biosecurity is the number one risk facing the agricultural industry in New Zealand, is genetic modification in all its forms, potentially our number one solution.

This also brings me to Kauri dieback. If we are unable to control the spread of the Phytophthora causing this disease then will we be left with the options of losing Kauri all together, or using GM technology to modify the existing genes within Kauri’s DNA to enable it to develop resistance. Are we better to have a GM Kauri than no Kauri at all?