Snowfall throughout December was sparse ( to say the least ) in southwest Michigan . According to Michigan State University’sKalamazoo Enviroweather station , the average day-after-day high temperature in the Kalamazoo area was 39 degree Fahrenheit with an accumulation of 91 degree - days above 32 F from Dec. 1–31 , 2018 . That is substantially warm ! These higher - than - average temperatures produce more rain than snow and left many wondering if winter would ever arrive . January , as you may have noticed , has been decidedly colder with an fair day-to-day temperature of 24 F and less than half of the accumulated point - solar day ( base 32 F ) of the previous calendar month . wintertime is here !
by Jeremy Jubenville , Michigan State University Extension
Spring craw statusThings are still a small quiet in most southwesterly Michigan greenhouses . cum houses and propagation way have been warm since December with bench and floors nearly full of warm immature plant ( Photo 1 ) . Most of these plant are n’t quite ready for transplant , however , so most production areas are still fair chilly and labor crew are small .
Photo 1 . Bedding plant seedling in a Michigan commercial-grade nursery . photograph by Jeremy Jubenville , MSU Extension .
DiseasesDisease pressure has been very low in southwest Michigan greenhouses . With that said , about every propagation house I ’ve claver has at least one crop sputter withBotrytisor some timeserving pee mold . In special , I ’ve seen problems with culinary herbaceous plant ( Photo 2 ) , canary annexe begonias andHelichrysum(Licorice flora ) . This is perfectly normal and due for the most part to the fact that unrooted cut can not be allowed to dry down or they ’ll go . Some plant species , however , really do n’t like getting water on their leaves and are very sensitive to wet foliage ( e.g. , Rosemary ) . To get around this problem , agriculturist will often create " tents " or wrangle covers using a geotextile textile . This helps keep foliage drier , but allows lightheaded , heat and humidity to get hold of the stock-still cutting . If you ’re struggling withBotrytis , regard building a Reemay ( or exchangeable product ) tent for the next crop and see if it facilitate .
Photo 2 . An irruption of Botrytis in rosemary production . pic by Jeremy Jubenville , MSU Extension .
For related to information , check out the excellent article W. Garrett Owen has written on how tomanage wet in vegetative cutting propagation .
InsectsBy all account , thripsnumbers have been average to below norm . I have not seen much damage at this compass point in the time of year , but sometimes damage does n’t become apparent until much later when it ’s too late ( e.g. ,Fuchsia ) . TheMSU Extensionfloriculture teamencourages grower to follow up a scouting and monitoring curriculum at their glasshouse . This can be as childlike as deploying yellow sticky hole and counting the number of catch thrips every calendar week . Dave Smitleyfrom theMSU Department of Entomologyprovides prompting in his annualgreenhouse pest management recommendations .
wanderer miteshave been find inBidens , Vinca vine , Diasciaand Dracaena “ spikes . ” Although I have n’t seen them yet , it ’s always good to keep an heart on crop likeCordyline , Mandevilla / Dipladenia , IpomoeaandHederaivy . They can be found by inspecting the underside of lower leaves with a hand lense and are large enough that all life stage are easily seeable . They pierce single plant cells and suck out the contents , so the damage looks like yellow - white speckles as if someone rub the folio with sandpaper .
The telephone number of plant species on which we findbroad mitesgets larger every year . So far this time of year , we ’ve ascertain them onSalvia , Thunbergia , Crossandra , Alternanthera(a new one for me!),FuchsiaandHederaivy ( cv . ‘ Gold Child ’ ) . It ’s also good drill to monitor rough-cut hosts such as New Guinea impatiens , begonias andScaevola . Finding them with a paw lens is certainly possible , but it can be a very difficult when populations are small . all-inclusive mites have toxic spit and feed in preferentially on newfangled tissue , so attend for brittle , hardened leaves and bud at the top of the plant .
Aphidswere establish in somePortulacaearlier in the calendar month . Some early seasonwhiteflieshave been discover inLamiumandSalvia(cv . ‘ bleak and Blue ’ ) . January temperature favor universe of the greenhouse whitefly ( genus Trialeurodes vaporariorum ) over the more heat - make love silverleaf whitefly ( Bemisia tabaci ) , which has become more difficult to control . Please get hold of a member of theMSU Extension floriculture teamif you ’re struggling to control a whitefly plague . We ’re glad to identify the metal money and hash out direction options .
Early season pest control is critical for tardy season success . Pest populations produce exponentially and they build up quicker with warm temperatures . assume a little redundant time to monitor and deal infestation in January can be enormously helpful in April and May when the temperature are higher and everyone is busy . established management product suggestions for all pesterer mentioned in this clause can be determine in the “ Greenhouse Pest Management with Insecticides ” tip weather sheet .
author : Michigan State University
