In a previous post, we wrote about the sheer volume of food that is lost before it gets to consumers. While the amount of food lost at different parts of the supply chain differs according to the level of development of the country (specifically the available resources to mitigate crop losses), there are some common elements. Furthermore, what is becoming extremely clear is that climate change will exacerbate some of the threats to production. In this post, we look specifically at threats to fruit and vegetable production. As a disclaimer – a single post cannot sufficiently describe all threats to food supplies.
The role of bees
In their book “A World Without Bees”, authors Benjamin and McCallum note that one in three mouthfuls that the average person eats, is as a result of pollination by bees. That’s quite an impact from an insect – around 90 commercial crops globally are dependent on bees for pollination. So, why is pollination important? Remembering back to high school biology, pollination is the process of fertilizing a flower so that that flower can turn into a fruit. There are some fruit species that are wind pollinated, but, this as a form of pollination, is limited to around 10% of flowering plant species. How does the lack of pollination form a threat to food supply – not, specifically as a loss of crops but more as a crop failure? If pollination has not occurred, then there simply is no fruit. Modern beekeeping struggles against issues such as colony collapse disorder (CCD) (more than 10 million beehives were lost to CCD between 2007 and 2013), and bee diseases such as American foulbrood and Varroa mite. Without bees and other beneficial insects and birds freely pollinating fruits and crops, the production volume is severely limited.
Frost and extreme weather events during plant growth
Assuming that pollination has occurred, and fruit has ‘set’, then another battle is the elements. Extreme cold weather when the fruit or vegetables are in a vulnerable state will either destroy or mark a crop. During the winter, fruit trees can cope with extremely cold temperatures, but, from the time that the blossom buds start to swell (before they become a flower) the fruit is vulnerable to frosts. The amount of vulnerability depends upon a number of factors including the stage of the blossom or fruit, the minimum temperature and the length of time exposed to the cold. A prolonged frost at the wrong time will see the loss of entire crops. To reduce the impact of frost damage, the horticulture sector employs techniques that increase the temperature or that protect the fruit. Temperature around a horticultural area can be increased through the use of helicopters or wind machines / frost fans – these work to move warmer air held in the inversion layer to the area around the trees, in effect, warming the air. This method is dependent upon the presence of an inversion layer and in its absence, other methods such as burning diesel-fuelled frost pots is required. Another method commonly implemented is the use of over-head irrigation to protect blossom or young fruit. The water forms a protective barrier around the fruit, stopping the temperature in the fruit or blossom from dropping too low. As the water freezes around the fruit, energy is released, effectively keeping the fruit ‘warm’. Crop loss can be significant: for example, an unseasonal spring frost in 2016 destroyed 90% of New England’s stone fruit (peaches, apricots, plums, and nectarines).
Protection from critters
If the fruit survives the frost, it is also susceptible to insects, birds, mould and bacteria. To reduce crop losses a variety of horticultural sprays are used. Although spray use has decreased markedly over recent years with greater understanding of pest and disease management, some sprays are still generally used to maintain crop volumes. There are specified maximum residue limits (MRL) for all horticultural sprays – these are determined as the level of spray that is allowable at which it is deemed to not cause human health issues. The interesting thing about these is that they can differ from country to country (as an aside, an interesting comparison on what is allowed and how it differs can be found for the example of tea here).
The horticultural industry must manage both the microscopic and the not-so-small. Bird damage as fruit ripens results in a large amount of fruit being deemed not fit for sale and human consumption. Measures to reduce the impact of birds includes netting, shooting, bird-scarers and even harnessing the power of other birds – falcons. One US study found that the cost of bird damage to honeycrisp apples was over $7,000 USD per hectare in Washington State, and the authors estimated that across 5 US states, over $189 million dollars of produce was lost in one year to bird damage.
The weather continues to challenge
In addition to frost fighting, the horticulture sector is beholden to weather throughout the production period. Hail storms when the fruit is still on the tree results in marked or damaged fruit, often unsuitable for sale. Of course, an appropriate amount of sunshine is required at the right time to ensure ripening, and while rain is required for irrigation at the ‘wrong’ time for cherry production, it leads to split fruit that cannot be sold. To reduce the impact of rain damage on cherries, growers will often use helicopters to dry fruit (obviously while it is still on the trees).
And, then consumers get fussy
Assuming pollination has occurred, fruit has set, frosts have been averted, and no hail, wind or rain damage has occurred, then fruit and vegetables are sorted for sale. It is at this stage that around a further 4% of fruit and vegetables in North America and Oceania (according to the FAO Global Food Losses and Food Waste report) are lost. Why? Often misshapen or irregular fruit, fruit that is bruised, over-ripe or damaged, is discarded as it is assumed that it will not be attractive to consumers. Given the amount of effort and potential for catastrophe along the supply chain, we should be viewing the fruit and vegetable section of the supermarket as a sort of celebration of miracles. A place where so much behind-the-scenes work has had to occur to ensure that our apples are perfectly formed, ripe and ready for consumption – it’s an interesting food for thought that one of the most uncomplicated products in the supermarket is actually based on an extremely fragile and vulnerable production cycle.