[MAIPC] last thoughts for the year on SLF

[Richard Gardner]

 What I havebeen learning in the last week or so is that the apparent chaotic egg layingand the coating on top of the egg masses, with subsequent color changing andcracks developing may in part be the SLF camouflaging the egg masses from theegg predators which it experienced in Asia. When I looked at the local treesand the egg masses, there are a lot of similarities between the egg masses,lichen, cankers and similar on the bark of trees. However, this is not Asia, soI cannot say exactly what the Asian vegetation looks like.

 An issue Icame across today was that gypsy moth habitat and SLF habitat overlap and theireggs may be laid on the same trees. The only difference I see is that SLF isconfined to the edge of forests, hedgerows and other ecotone areas since thisis where its primary foods are located. The gypsy moth lays eggs on treeswherever it finds them, including the deep forest, the edge of forests,hedgerows and trees in cities. Gypsy moth egg masses are light brown foam whileSLF egg masses are smooth, going from dirty white to light tan in a few days(?) after laying. I am not sure if gypsy moths and SLF feed on some of the sameplants. The timing of the egg laying is different. Gypsy moths tend to lay eggsmid to late summer. SLF egg laying appears to be late summer to a killerfreeze. The timing may be based on the preferred foods of each. Gypsy mothlarvae feed mostly on the leaves of deciduous hardwoods, which come into leaf latewinter to mid-spring. This is much earlier in the year than Ailanthus, whichcomes into leaf in the late spring, one of the last trees to do so. Emergenceof the immature stage for both may also be related to their food sources andfeeding method. Gypsy moth larvae feed by chewing and digesting leaves. This isvery different than the SLF nymphs and adults drilling into a plant and suckingthe sap. I am not sure how much ahead of bud break and leafing out sap runs in Ailanthusor how much after leaf drop it continues.

 One lastobservation I made today is that I found SLF eggs only on grey birch trees inand surrounding the stand of Ailanthus trees. No egg masses were found on Ailanthustrees where I had seen SLF earlier in the fall. Reviewing the photos fromearlier today, there were generally one to three egg masses on each white birchwhere the eggs masses were found. As usual there was no apparent order in thescattering of the egg masses within the white birch stand. This needs more timewalking to see of this is generally true in other areas.

 A generalongoing observation is that I have seldom seen SLF egg masses much higher than 4 or5 feet off the ground. The one obvious exception is on domesticated silvermaple.

I sincerely wish this SLF project were a tame onelike the American Chestnut research I have been doing, with a definitive startand end to the field season. Now that leaf drop has happened the darkened treesSLF fed on are more obvious and it is easier to see egg masses. This is takingon the feel of continual year-round research.
                                               Richard Gardner
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