No silver bul­lets for pest man­age­ment

A cri­sis of pest man­age­ment is com­ing shortly but there are no silver bul­lets, Travis Glare from the Bio-Pro­tec­tion Re­search Cen­tre warned onion grow­ers at the Onions New Zealand’s re­search sem­i­nar.

NZ Grower - - PRODUCT GROUPS - By Glenys Chris­tian

“If we didn’t have pes­ti­cides 83% of food would be lost at the pro­duc­tion stage,” he said.

“But de­vel­op­ment of new sprays is more ex­pen­sive now. Mono­cul­ture is the eas­i­est way to farm but we are mak­ing a prob­lem for our­selves.”

Glare said a leap of faith had to take place for grow­ers to stop us­ing chem­i­cals, but large chem­i­cal com­pa­nies were al­ready buy­ing bi­o­log­i­cal com­pa­nies be­cause they saw the po­ten­tial mar­ket size.

The Bio-Pro­tec­tion Re­search Cen­tre is a na­tional cen­tre of re­search ex­cel­lence, founded in 2003, which has six part­ner in­sti­tutes: Lin­coln, Can­ter­bury and Massey Uni­ver­si­ties, AgRe­search, Plant & Food and Scion. It fo­cuses on fun­da­men­tal re­search into nat­u­ral, sus­tain­able ways of pro­tect­ing New Zealand from plant pests, dis­eases and weeds.

There were no silver bul­lets but user-in­spired ba­sic re­search would still be car­ried out with goals in mind.

“There are big ques­tions such as why some strains of bac­te­ria cause prob­lems and some don’t?” he said.

“We need to know where evo­lu­tion is go­ing and steer it as we try to work out how ev­ery­thing in­ter­acts.” Glare said the cen­tre tried to get a lot of sci­ence be­hind what it was do­ing.

“With weeds we want to know why they cause prob­lems,” he said.

More than 25,000 plants had been in­tro­duced to New Zealand but only 2,523 had be­come prob­lems.

“Is that be­cause they escape from their ene­mies, evo­lu­tion or some sort of hy­bridi­s­a­tion?

“It could be all three and we need to pre­dict which ones may be­come prob­lems.”

With par­a­sitoids, he said one which con­trolled Ar­gen­tine stem weevil was in­tro­duced in the 1990s.

“But it has started to be­come less ef­fec­tive and we are try­ing to work out why.”

The genome of the weevil had changed since it had been in this coun­try due to rapid evo­lu­tion, but the asexual par­a­sitoid had not. While the par­a­sitoid could be changed to be male or fe­male they could not then be re­leased as they could breed with the Si­tona weevil and then be­come less ef­fec­tive on both in­sects.

More in­for­ma­tion was re­quired on how plants and dis­eases com­mu­ni­cated in order to breed plants with more re­sis­tance. But there were

prac­ti­cal is­sues about how to get an­tibac­te­rial agents into plants.

“It’s a grow­ing area and more than one or­gan­ism can be used,” he said.

“But ge­netic en­gi­neer­ing is wait­ing for pub­lic and trade ac­cep­tance.”

Work was be­ing car­ried out with en­hanc­ing bio­con­trols as ev­ery plant had en­do­phytes and there was the po­ten­tial to use them to im­prove plant growth and in­sect re­sis­tance. Work was also be­ing car­ried out with maize and bras­si­cas try­ing to find new en­do­phytes, but this was dif­fi­cult with 15 types of fungi found on one maize plant when it was pulled up. >

“Gene edit­ing could be used to take out one piece of DNA tar­get­ing plant breed­ing, but there were eth­i­cal ques­tions as to whether this was ge­netic mod­i­fi­ca­tion.”

Work was also be­ing car­ried out on im­prov­ing bi­o­log­i­cals with over­ex­pres­sion of bacil­lus thuringien­sis (BT) be­ing in­ves­ti­gated.

“By se­lect­ing clever cul­ti­vars big­ger plants are the re­sult and this can re­duce dis­ease im­pact,” he said.

Plants had mi­crobes all around them, cre­at­ing their mi­cro­biome, which large com­pa­nies were in­ter­ested in de­vel­op­ing fur­ther.

“We have the tools to look at them,” he said. When it came to the ap­pli­ca­tion of con­trol agents there was still a road­block, but

a new pre­ci­sion agri­cul­ture tech­nique, fog­ging, was an ap­pli­ca­tion tech­nol­ogy which could be used.

“We can se­quence ev­ery or­gan­ism and look at any vari­a­tions in growth around the coun­try.”

Where biopes­ti­cides had been ap­plied there had been some in­con­sis­tent re­sults.

“Ev­ery plant is chang­ing its own en­vi­ron­ment,” he said.

“Each grass grub pop­u­la­tion, for ex­am­ple, is a sep­a­rate mi­cro­bial com­mu­nity. We’re ask­ing if we can use that and ma­nip­u­late it to get them to eat roots, for ex­am­ple.”

Glare said a move was now un­der­way from the genome to the pro­teomic area.

“The tools we’ve got now are fan­tas­tic and we’re get­ting to an era where the species is not im­por­tant but the genome is,” he said.

Trans­genic crops such as cot­ton and soya beans were the re­sult of sin­gle ac­tion gene changes so it had been easy to get re­sis­tance. The next step would be to move on to more than the top five crops around the world.

Gene edit­ing could be used to take out one piece of DNA tar­get­ing plant breed­ing, but there were eth­i­cal ques­tions as to whether this was ge­netic mod­i­fi­ca­tion.

Gene drives had only been car­ried out in lab­o­ra­to­ries, where a mod­i­fied or­gan­ism was re­leased into the pop­u­la­tion and drove it to ex­tinc­tion.

“But they will re­pair them­selves,” he said. “There are still a lot of tech­ni­cal is­sues. We have to make a trans­genic or­gan­ism to do this and that’s not pos­si­ble at the mo­ment. We also need an idea of pop­u­la­tion ge­net­ics be­cause it won’t be as ef­fec­tive in some sys­tems.”

Asked by a grower about hy­per­vir­u­lent strains emerg­ing he said he didn’t know how this would hap­pen.

“If any or­gan­ism is too vir­u­lent it kills all its hosts and then dies out it­self.”

Drones, which he de­scribed as “the de rigueur [fash­ion­able] idea of how to do bet­ter agri­cul­ture” were able to mon­i­tor plant health as well as carry out very tar­geted spray­ing.

“The tech­nol­ogy is there and it’s go­ing to hap­pen quite rapidly,” he said.

Pre­ci­sion agri­cul­ture ap­pli­ca­tion could be used in com­plex grow­ing sys­tems.

“You don’t need to use an ex­pen­sive spray on the whole pad­dock, just where the prob­lem is.”

Bet­ter un­der­stand­ing of mi­crobes which were hard to see and com­plex, could be gained by mescosm study, an out­door ex­per­i­men­tal sys­tem which mea­sured ev­ery­thing hap­pen­ing to a plant un­der con­trolled con­di­tions. An 18-month ex­per­i­ment was be­ing car­ried out now at Lin­coln Univer­sity with broom, which it was hoped would un­lock in­for­ma­tion as to why it was more in­va­sive in some ar­eas than oth­ers.

Glare said com­mu­nity in­volve­ment was also re­quired in some re­search ar­eas, as some ques­tions kept com­ing up.

“It’s not the sci­en­tists’ job to an­swer these ques­tions, we just put up the in­for­ma­tion,” he said.

“We also need to de­velop ca­pa­bil­ity for a smart work­force as few New Zealand stu­dents go on to post-grad­u­ate stud­ies.”

They of­ten got jobs in in­dus­try quickly which at present meant 75% of post-grad­u­ate stu­dents at the cen­tre came from over­seas.

▴ Travis Glare – big ques­tions to be asked.

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