Hi Tui, I recently sprayed my lemon tree for aphids with what I thought was an old commercial mixed pyrethrum spray, from what I thought was a clean spray bottle! In an hour the new growth had wilted, and subsequently the leaves developed lots of brown spots and and the lemons looked like something was etching into the skins. I’ve cut back to what appears to be healthy branches. What I am concerned about is : is the fruit safe to eat?? And do you have any idea what it was I’ve sprayed?? I am at a loss to know whether the spray bottle had a residue in it, or the commercial spray gun of pyrethrum was somehow tainted, due to its age?? Thanks.

Hi Jennifer, that is a very sad lemon tree. Firstly, was it sprayed in the middle of the day in full sun? Best practice is to spray in the early morning or late afternoon when bees aren't foraging, but also so the spray does not burn the leaves. Water on foliage in the midday sun acts as a magnifying glass and will burn the foliage and fruit. Secondly, it is hard to say if the pyrethrum in the spray bottle was something else or the spray bottle was tainted. If it is a concentrate mixture that has been left in the spray bottle for a period of time, mixed up spray should only be kept for 24 hours maximum and disposed of after that, it is not a good idea to leave spray mixed up in the sprayer. Sometimes we forget what we have mixed up and can make a mistake. If it was a commercial Ready to Use pyrethrum spray it shouldn't cause that sort of damage, and should be good for at least 3 years if stored correctly. Remove the fruit as this will be causing additional stress to the plant, as you are uncertain of what was in the sprayer the fruit should be disposed of and not eaten. Cut the tree back by approximately one third. Feed with Tui Organic Seaweed Plant Tonic at a rate of 100ml per 9L watering can and do this weekly until the tree starts showing signs of recovery. The potting mix looks very dry, increase your watering as well, don't feed the plant until it starts to show signs of recovery, use a controlled release fertiliser such as Tui Enrich Fruit, Citrus, Tree & Shrub fertiliser, only apply Seaweed plant tonic for now. The Tui Team.