Terrible season

In summary, this has been an absolutely terrible season, one of the reasons I haven't bothered posting much this year. To start with, no pollination as the insects didn't come out in the rain. The few pears that set are all abnormally small. Lots of scab on leaves and shoots. The quince set more fruit, but then a terrible attack of scab make everything drop off. The medlar set a lot of small fruit but it has now all browned off and rotted on the tree.

The plums were similarly affected, either no fruit set, or a small number of undersized fruit (which was all taken by the rogue squirrel anyway). The apples have done better, but with a fair amount of cracking or scab, and the early varieties have largely been spoiled by jay or squirrel damage before they were ripe enough to be picked. 

This has been by far the worst year we've suffered here, normally only one or two susceptible pears are affected by fungal ills, but this year everything has suffered in some way or other from the terribly wet weather. So there will be no boxes overflowing with lovely clean, large, beautiful fruit this year. Very depressing and disappointing, I have been so ill this year it would have been lovely to have had something cheering to look forward to.

War on Squirrels and Jays

Having posted on how well the codling moth traps were working, I can't say the same of the squirrel trapping. We have had a huge influx of squirrels this year, and one in particular seems impossible to trap. They have just stripped the Denniston's of its small crop completely and are randomly biting into our small crops of apples and pears. I trapped one last week, thinking at least that only left one hard nut to crack, but I'm blowed if another two didn't appear almost immediately. 

In addition to crows this year jays have done an extraordinary amount of damage. I'd been wondering what had been hacking lumps out of my Grenadier, and then moved on to the Worcester and my un-named early red. I'd been thinking it must be pigeons but then I caught a jay actually doing it shamelessly right in front of me. We have a very active extended family of jays which are continually attracted to the area by a neighbour who tips peanuts into his garden as if they were garden mulch, one reason for the influx and high breeding numbers of squirrels. 

I hope the jays may be a temporary problem. They haven't been a problem before, and I think they initially started pecking at the fruit because of scab-related soft patches on the fruit. Having started off with these, they then discovered that the rest of the fruit was palatable. I hope they don't remember next year, but they are bright corvids and they do have a remarkable capacity to remember and teach others of their kind. If they don't forget, then sadly we'll be getting towards the stage of having to net everything soon.

Pheromone traps - verdict

Really pleased with the traps, despite reservations they worked well. Sadly the plum didn't set any fruit at all, so no way of evaluating how well the trap worked other than to count the moths, but the one attached to Rosemary Russet caught approximately 10 moths and there is no sign so far of any holes in the surprisingly good crop on this cordon, and that without spraying. Unfortunately, the full standard Grenadier on the other side of the garden is full of the things again, so clearly they aren't effective over a very large area, and I'd need at least one more to help clear the problem over the full area. But certainly well worth trying again next year.

Mea Culpa - pheromone traps

I meant to post quite a while back that I'd decided to try moth pheromone traps for the first time as a couple of apples and one plum are very badly affected by the relevant species. I bought some from a common-or-garden centre in Bicester, and managed to get them both in place by mid may. 4 codling moths appeared in the trap around the last couple of days of the month, and I notice the first plum marauder turn up about a week later. All dark, dull, undistinguished moths  about 5mm long. My aim was to spray the trees soon after to catch the tiny caterpillars just before they started to burrow their way into the fruitlets, but the weather was so bad that it was just impossible. Yesterday I found a nice, plump fruitlet with a pin-sized hole, and cut it open to reveal a surprisingly large grub around 4-5mm long, so it's now completely pointless attempting to spray the affected apples; I will try to spray plum tomorrow, deluges-permitting.


The moth 'reservoir' Grenadier tree in the new plot of land has been thinned by one third for the third year in a row, so that hopefully there will be fewer infected windfalls to dispose of or infect the neighbouring garden, as well as the hope of better quality fruit overall. 

Frass on Quince

I noticed lots of insect frass on the calyces of a couple of quince this year. Quince are famous for having few pests or diseases, so I was a bit annoyed to find this as well as quite a lot of scab. However, on close inspection the damage is mainly on the exterior, extending only a little way into the fruit at the calyx end.

I'm not sure what did the damage, I couldn't find anything among the frass or inside, but I think whatever it was, it's an opportunist bug of some kind rather than a serious specific pest of quince. I'll need to keep an eye out for it, as even this small amount of external damage will rapidly turn to brown rot in store.

Codling control - the results

Slightly disappointing results for codling moth control. Picked several bored fruits off Pixy and Orlean's Reinette. I've come to the conclusion that the worst affected varieties are those where fruit is bourn in clusters that are very tight, sheltering the caterpillers sufficiently to bore into the fruitlets hidden from predators. I think the nematode treatment was worth doing, as I haven't found any on varieties other than these two yet. In future, I think I'll try spraying these varieties individually, using pheromone traps to identify when the adult moths are on the wing.

Final Nemasys treatment

Final Nemasys treatment was applied last Monday, a couple of days over the suggested interval of 7 days, due to lack of time and terribly strong winds.

Pest: codling moth damage on pears

The first pears to fall were all infested with some kind of fruit-mining larvae. This time I'm inclined to think the culprit is codling moth, rather than fruit mining moth which was a problem last year. The latter tends to make multiple tunnels nearer the surface, whereas the damage here is mostly to the core with one escape tunnel.

Only a handful of fruit were infected, so not a major problem as yet. If the numbers increase next year I might have to think about controlling it down the line, but not at the moment.

More about codling and other fruit-mining moth damage to fruit.

Squirrel damage

This has been an awful year for squirrel damage, with significant losses on some varieties. All the apples on the Worcester Pearmain were removed or damaged, the blighter then moved further up the garden to the pear cordons. Worst affected was Winter Nellis, where 2/3rds of the crop were nibbled and subsequently lost to brown rot. Nearly as bad was Devoe, where very few of the fruits escaped being bitten. Some bite marks will heal and go corky as with scab damage, but I doubt they will keep well. 

It took me a long time to catch the culprit, as there were several squirrels around and the fruit-nibbler was also the most wily. Plus my squirrel trap disappeared one night, whether taken by two-legged or four-legged vermin I don't know. I imagine squirrel trapping probably upsets some of my neighbours (particularly when they devote quite a large proportion of their income to feeding both them and the local rat population) but the losses they inflict on fruit are unacceptable, and it would be completely impractical to cage a quarter of an acre. The damage stopped immediately with the removal of the last squirrel.

Harmonia axyridis - a new fruit pest?

We've been concerned for some time about the rising numbers of Harlequin Ladybirds (Harmonia axyridis) and the effect they will have on native ladybird ecology, including the predation of native ladybird larvae. However, I hadn't realised until now that they can also be pest of fruit. In addition to feeding on aphids, they will also suck ripe and soft fruit in late summer, and even damage the skin of pears. I haven't noticed any damage here, but the numbers continue to rise inexorably, so it may well become an issue in the future. 

Harlequin Ladybird Survey

New pest - Jays!

A pair of jays have moved in nearby, and their preferred nesting material appears to be fruit tree ties, which they are quite adept at removing. I suspect the string probably isn't doing a lot if it comes away this easily, though they have made sterling attempts to removed newly knotted ones as well. 

Wasps

I've never really had any problems with wasps before, largely because I watch my fruit ripening like a hawk and whip it off the moment I think it's ready (or just before). Consequently the wasps have rarely had an opportunity. In fact, I was struck that numbers were unusually low in 2008 and 2007.

Having had to leave fruit ripening on the tree while I was away, they have now reappeared in swarm proportions with a vengeance. I'm sure there will be complaints if I don't do something, as this tree is dropping wasp-covered fruit on the pavement. They are extremely efficient at eating whole fruits, sometimes excavating away leaving just the skin like a deflated balloon.

I managed to pick about a kilo of Morettini today before giving up. I don't have a great fear of wasps, having been covered by them many time while picking blackberries very early in my youth and never stung, but the risk of grasping one while picking was too great. I returned after dark tonight to clear up fallen/rotten ones, and pick the remainder of the crop. Even so, quite a few wasps were still crawling around, still inebriated from gorging on the fruit.

more squirrel damage

Having had to spend so much time in Wales as my father is so ill, I haven't got round to removing any squirrels yet, and they are beginning to be a nuisance again. Quite a lot of fruit has been ruined on this Worcester Pearmain. Rot has already set in, and all damaged fruit will be useless.

Woolly aphid

A bad attack of woolly aphid on Orlean's Reinette. In past years they have occasionally congregated on rootstock burrs, but this attack is more extensive. I'll prune the affected new growth off completely and discard, and treat the rest with a cloth soaked in meths.

War on squirrels

This is another excellent example of squirrel damage on a pear crop, this time on my only crop of Dr Jules in 5 years. Although holes and shallow depressions can also be caused by moth damage, there are clear incisor teeth marks. The trap goes out first thing tomorrow before they ruin the remaining fruitlets.

More Fruit-mining Tortrix damage?

Now that the fruitlets are growing on, more caterpillar damage is becoming evident. I think a fair number will actually survive to produce usable, if blemished fruit. 

Insecticides?

The moth larvae attack is turning out to be quite bad, lots of fruitlets bored or nibbled on the outside. Mostly on the Conference/Concorde cordons, with minor damage on the adjacent Comice/Beth (an one or two nibbles elsewhere). 

However, there remains the dilemma of what to use. I've never had cause to spray for insect attack before, only the occasional dose of Bordeaux on scab-susceptible varieties.

Derris is the only insecticide recommended by the Soil Association. The active ingredient is Rotenone. However, all rotenone-based insecticides were banned for public use last year, presumably due to the suspicion they might cause nervous system damage.

Hort. Week: Derris Banned

Pesticides.gov advice

The only other choice are Bifenthrin-based inseciticides (Bug Clear), a pyrethroid compound which is also a neurotoxin. Just because such insecticides derive from plant-based substances does not make them any safer, ethical or 'natural'. Bifrenthrin isn't terribly water-soluble. Hopefully that means it won't leach straight into the water table. However, it means it's more likely it will persist in the environment.

In the end I did spray only the Conference/Concorde cordons with Bifenthrin/Bug Clear this morning. We have no Blue tits nesting this year, may be they had kept the infestations at bay in previous years, and my fear is a explosion in the population if the pest goes unchecked in this season. Hopefully this will redress the balance, and the birds will be back next year. The fact we've also had a really bad attack of Gooseberry sawfly for the first time in the last decade suggests there is some change in the pest/predator balance this year.

I'm not going to rant about 'elf and safety gorn mad. We don't know what the effects of these substances are in the environment because ecosystems are enormously complex and difficult to study. Years ago, arsenate of lead and nicotine were popular and highly effective insecticides. On the other hand, pests can destroy whole crops and commercial growers will all spray regularly as a preventative measure so the fruit-eater doesn't escape the issues either way.

Fruitlet Mining Tortrix?

Another new nasty today, I think it's probably a Fruitlet mining moth (Pammene rhediella ) though I have my doubts as the colour and 

season seem slightly wrong. 

Which ever species it it, this one is 

rather more damaging, as it bores right into the fruit. 

I've only found it on Conference so far, perhaps because the long 

fruitlets are set close together, giving it more shelter. It usually joins two fruitlets together with silk, which is the best clue to spotting it.

More on the various Tortrix moths

Fruit Tree Tortrix Moth

Curled leaves, which usually unravel to reveal a medium-sized green caterpillar (Archips podana, the Fruit Tree Tortrix) usually sitting amid a web of silk and frass of droppings. 

Not a lot to be done, especially as the leaves bound with silk are an excellent way of escaping any spray treatments. I usually pull curled leaves off when I find them.

More in general about fruit tree caterpillars

Fruit-Tree Tortrix Moth Lifecycle

Unidentified guests

I have been wondering what had been making small holes on the leaves of a couple of pear cordons; the culprit is a looper-type caterpillar about 4 mm. It's not a Winter Moth Caterpillar. The holes don't really affect the plant that much so I will leave them in peace.

Another small brown looper caterpillar (about 8mm, NOT a mottled umber moth) has been slicing the edges off small pear leaves; again, it's not doing any real harm so I'll leave this one for the birds too.