The smell of pesticides in the morning

I had been a little worried that I wasn’t going to be able to find much research concerning the cut-lower industry, or that, if I did, it would all be about developing new varieties of popular flowers. In fact, I was surprised at the extent of the literature- researchers have been paying attention to multiple aspects of the industry for at least the last few decades. For this week, I’ll concentrate on the issues we might expect when thinking about cut flowers: pesticides, pests, and water use.

IMG_20140531_094809_686Growing beautiful flowers that people want to buy means making sure that they don’t show signs of diseases or parasites– in addition, flowers imported into the US and many other countries must be free of pests when checked at the border (Tenenbaum 2002). Since we don’t eat the imported flowers (generally), there aren’t always regulations limiting how much or what kinds of pesticides are used. A 1979 study testing flowers as they arrived in Miami found that 85% of samples had residue from at least one type of pesticide, and 16 different pesticides were found (Morse et al. 1979). Some of the samples even had levels that could cause reactions in people handling the flowers. According to a 2007 review, roughly 20% of the pesticides (insecticides, fungicides, herbicides, etc.) used for flowers in the developing world are either untested or not allowed for use in the US (Donohoe 2007). Simply saying that growers shouldn’t use pesticides is unrealistic- flowers are big business with sales hitting $30 billion in 2007, and it’s global trade that involves Holland, Columbia, India, Kenya, Malaysia, Mexico, and a number of other locations. But it’s very important to think about these issues- over 84% of workers in Bahong, Philippines reported going into recently sprayed areas (Lu 2005) and people applying pesticides on several farms in Uganda indicated that they did not have much access to protective gear (Munyuli 2014), plus those pesticides don’t just impact the people who work with them- they wash into rivers, affect non-target insects like bees, and can make their way into drinking water.

And it is important to keep floral pests from getting to new places. Chilli thrips are a big problem for rose growers in India and have been found in the US since 2005 (Mannion et al. 2013). Mannion et al.’s (2013) study in Florida found that regular fertilization of roses may make them important hosts for the thrips, which is important information- the thrips may like roses, but they attack at least 112 species of plants, including some that we use for food. Likewise, a fungus originally found in the US, Guatemala, and South Africa showed up on arum lilies in Brazil as a leaf spot disease (Vieira & Barreto 2004). As I’ve mentioned in my posts on invasive species, newly introduced species can overwhelm native communities and even cause species extirpation.

Water-use is another crucial aspect of the cut-flower industry where we face challenges. Fresh, clean water is becoming an ever-more scarce resource around the globe, and growing flowers both removes water supplies and releases water pollutants such as pesticides and fertilizer (Tenenbaum 2002). You might be surprised by the actual water impacts of growing flowers for sale- a study of Kenya’s Lake Naivasha area, where most of the country’s horticulture industry is based, found that the water footprint per rose flower stem was 7-13 liters– this includes both water used by the plant and water needed to absorb and dilute nitrogen run off from the farms (Mekonnen et al. 2012). That is a lot of water. When water use was compared with water input from precipitation and river flow, supply met demand only April-October per year. As might be expected, the lake level has decreased as surrounding horticultural activity has increased, and water quality in the lake has decreased as more and more nutrients are released into the waters.

So there are certainly concerns about how cut-flowers are farmed in terms of pesticide and resource use, plus we have to think about the global scale of the trade and all of the chances for nasty parasites and microbes to travel to new locations and wreak havoc. But the cut-flower industry also has social and political components, which I will look at next time. Plus I’ll describe how some groups and individuals have already recognized the environmental challenges and started working to mitigate the impacts.

Works Cited:
Donohoe, M. 2007. Flowers, diamonds, and gold: the destructive public health, human rights, and environmental consequences of love. Human Rights Quarterly 30: 164-182.
Lu, JL. 2005. Risk factors to pesticide exposure and associated health symptoms among cut-flower farmers. International Journ. of Envir. Health Research 15: 161-169.
Mannion, CM, Derksen, AI, Seal, DR, Osborne, LS and CG Martin. 2013. Effects of rose cultivars and fertilization rates on populations of Scirtothrips dorsalis (Thysanoptera: Thripidae) in southern Florida. The Florida Entomologist 96: 403-411.
Mekonnen, MM, Hoekstra, AY and R Becht. 2012. Mitigating the water footprint of export cut flowers from the Lake Naivasha Basin, Kenya. Water Resources Manag. 26: 3725-3742.
Morse, DL, Baker, EL and PJ Landrigan. 1979. Cut flowers: a potential pesticide hazard. Amer. Journ. of Public Health 69: 53-56.
Munyuli, BMT. 2014. Is the cut-flower industry promotion by the government negatively affecting pollinator biodiversity and environmental/human health in Uganda? ISRN Biodiversity 2014: 368953.
Tenenbaum, D. 2002. Would a rose not smell as sweet?: Problems stem from the cut flower industry. Environmental Health Perspectives 110:A240-A247.
Vieira, BS and RW Barreto. 2004. First record of Cercospora richardiaecola causing leaf spots on Zantedeschia aethiopica in Brazil. Plant Pathology 53: 813.