Saturday, August 22, 2020

Farm Diary: Neem's nemesis

Neem trees have almost mythical status in these parts. The wood is said to be largely termite- and pest-resistant. Neem oil has the reputation of being an extremely effective pesticide among organic ones. Neem seeds sprout in the most barren of lands here, muscle their way through the competition (mostly weeds and other brush) and establish themselves in no time. They may do a lot of things right but they have one big vulnerability. 

There's a family of parasites called Loranthus or mistletoes that seem to have Neem's number.  The seeds of the parasite usually end up on the branch of the neem tree through bird droppings. Once there, they grow roots on the branch and start to grow their own branches usually drooping down from the host's branch. For a while, because they match the colour of their host, they make the foliage look robust and healthy. Over time, though, they start to crowd out the neem's own leaves.The host's branches develop thick nodes out of which no new branches or neem leaves sprout. And then over the course of a season or two the host dies completely. 

I don't have the "before" photos but the picture above is of a neem which succumbed to Loranthus this year. As I take stock now I realise we've lost dozens of healthy trees to this blight. From my research on the net I didn't find effective ways to combat this parasite without the use of chemicals. We've been experimenting with pruning off the affected branches right after the initial infestation, and so far that seems to have worked. 

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