With warmer weather and longer days comes the awakening of a seemingly ever-increasing army of pests and diseases to contend with.
January 23, 2023 By Gary Jones
This time last year, I was writing about the major flooding affecting the Fraser Valley in B.C. due to “atmospheric rivers.” This year, I sit looking out on about 14 inches of snow that fell a few nights ago and temperatures dropped to -11C, and hear the freezing rain as it falls on top of that. Later today, apparently, the weather is due to warm up to +4C, and we need to be ready for severe flooding. YVR airport has effectively been closed for a couple of days, all the major highways are a glorious mess, and advice is not to travel anywhere. Despite this, when I do get out, I see the warming glow of HPS lamps at the local propagator reflecting from the low clouds, magnified by the whiteness of the snow beneath – signs of the new vegetable crops just ahead around the turn of the year. For me, it’s a wonderful sign of optimism.
But with this warmer weather and longer days comes the awakening of a seemingly ever-increasing army of pests and diseases to contend with. Tomato Brown Rugose Fruit Virus (ToBRFV) has now been with us for about seven years. In that time, it has been found in 35 countries across four continents and spawned what seems like its own research department. Syngenta have set up their “ToBRFV Information Center” to help inform of the disease. Cases have been found in pepper plants and it is known to infect over 40 species of plants across four families. Crop losses can be huge (up to 70%), and certainly more than growers should be expected to stand, economically. It really has become a disease for the ages. It is also occurring in unexpected places: “Recently, the Tomato brown rugose fruit virus (ToBRFV) was found in the basin water of a tomato grower in Belgium, while the virus had not (yet) been found in the greenhouse.”1 For a great review paper on ToBRFV, check out the Shaokang Zhang et al2 paper referenced in the footer. (All Canadian authors, I might add.)
Pepper growers are being warned to look out for a ‘new’ species of thrips; Thrips parvispinus. Primarily a pest of ornamental crops, this thrips is posing a threat to greenhouse vegetables, too, creating yield losses in bell and pointed pepper crops in Spain. “While causing damage to flowers and leaves similar to Western Flower Thrips (WFT), T. parvispinus also inflicts characteristic damage to growing points, causing stunted growth. Heavy infestations cause damage in the young leaves, which sometimes resembles broad mite damage. Damaged fruits may subsequently stick to leaves and exhibit brownish, and sometimes wet, spots,”reports Koen Merkus, IPM and Pollination Specialist at Biobest in HortiDaily.3
The emergence of new pests and diseases is not because a brand-new species of insect, virus or fungal pathogen is suddenly created, of course. But for whatever reason, the causal organism finds opportunity to gain a foothold where not seen before. So, what do we do about such new troubles? There are several strategies to consider for dealing with any or all of these new pests/pathogens:
- Stay informed: Keep up to date by talking to colleagues, consultants, reps., educators, researchers, conferences/seminars, and following in the press.
- Start clean, stay clean: Prevention ought to be better than eradication, but it may not be easy nor foolproof. But just because it may not be 100% achievable shouldn’t mean you ignore it or don’t try to do it. Quarantine, sanitation, general hygiene protocols should all be a regular part of doing business.
- Stay ahead: Use resistant varieties, as they become available and commercially competitive.
- Stay the course: Use all possible control options – biological, cultural, mechanical/physical, chemical, even legislative ones, if you’re unfortunate to have notifiable pest outbreaks (If you use a plant vaccine, make sure it’s legal!)
- Stay alert: Follow what’s going on in other sectors as to what might be in the pipeline for your crops.
I’ve always found growers to be resilient, inventive, curious and able to come up with or embrace solutions offered to them to overcome the challenges thrown their way. I have no doubt that this will continue.
1 Robert de Hoo, reported in www.HortiDaily.com December 2021.
2 Shaokang Zhang et al, (2022) “Tomato brown rugose fruit virus: An emerging and rapidly spreading plant RNA virus that threatens tomato production worldwide.” In Molecular Plant Pathology, accessed at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9366064/ Dec 23 2022.
3 “Pepper growers should remain vigilant for new thrips threat” https://www.hortidaily.com/article/9489804/pepper-growers-should-remain-vigilant-for-new-thrips-threat/ www.HortiDaily.com December 23 2022.
Gary Jones sits on several greenhouse industry committees in B.C. and welcomes comments at firstname.lastname@example.org.
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