Southern Kemptville, Pembroke, Algonquin Park Districts Aspen Zeppa 613-258-4072 or aspen.zeppa@ontario.ca
IN THIS ISSUE Ontario’s Forest Health Program Update Fall webworm Walnut lace bug Bronze birch borer Pine engravers Eriophyid mite Birch sawfly Maple tarspot Tubakia leaf spot
Ontario’s Forest Health Program Update Forest Health Update – August 2010 The following is a forest health update for the Algonquin Park, Pembroke and Kemptville districts of the Ontario southern region. This edition will describe and summarize entomological and pathological events affecting the health of the forests in these three districts which occurred during the later portion of the growing season of 2010. This report was prepared by Aspen Zeppa of the Ontario Ministry of Natural Resources. Any questions or comments can be directed to Aspen Zeppa by telephone at (613)258-4072 or by email at aspen.zeppa@ontario.ca .
This year the Forest Health Program has undergone some major changes, ranging from the MNR realignment where our program was moved into the Science and Information Branch to many staffing movements and shortfalls. We are all working strenuously to meet our deadlines and project requirements in order to fulfill our program needs. During our staffing movements we have seen Patrick Hodge move to fulfill Ed Czerwinski’s position in Peterborough and Bancroft districts. Susan McGowan has moved to Aurora and Midhurst districts in place of Patrick, and I have
Southern Kemptville, Pembroke, Algonquin Park Districts Aspen Zeppa 613-258-4072 or aspen.zeppa@ontario.ca moved to fulfill Susan’s position in Kemptville, Pembroke, and Algonquin Park districts. Steen Anderson covered Thunder Bay and Nipigon districts for the majority of the growing season and Timmins, Cochrane, and Hearst districts are not currently being covered by a Forest Health Technical Specialist. As I have just moved to this area in late august, this report will cover only insect and disease damage that was confirmed in this short period. The Forest Health team are still working in conjunction with the Forest Health and Silviculture Section and finding direction with the help of the Provincial Entomologist, Taylor Scarr, and the Provincial Pathologist, Richard Wilson as well as other specialists. We also continue to work with the Ontario Forest Research Institute and the Great Lakes Forestry Centre who provide us with diagnostic expertise in insect and disease identification among other things. Fall webworm Hyphantria cunea (Drury) Fall webworm was collected from large tents in Bastard and S. Burgess Township, Kemptville District where it was causing approximately 40% defoliation to road side white ash (see figure 1). This insect has one generation per year and is a late season defoliator. Repeated defoliation may weaken the tree; however it is unlikely to kill it.
Figure 1. Fall webworm damage to white ash in Kemptville district. (Aspen Zeppa, Sept. 2010)
Walnut lace bug Corythucha juglandis (Fitch) The walnut lace bug was observed to be defoliating the underside of leaves on a hybrid butternut tree (see figure 2). The defoliation is estimated at less than 5%. This collection was made in South Gower Township, Kemptville District.
Southern Kemptville, Pembroke, Algonquin Park Districts Aspen Zeppa 613-258-4072 or aspen.zeppa@ontario.ca At least 20% of the tree had crown die-back. The bronze birch borer is capable of causing mortality to birch trees, especially where trees may be stressed by other factors. Pine engraver Ips pini (Say) Southern pine engraver Ips grandicollis (Eichh.)
Figure 2. Walnut lace bug on the lower leaf surface of a hybrid butternut tree in Kemptville District. (Aspen Zeppa, August 2010)
Bronze birch borer Agrilus anxius Gory
These two engraver beetles were collected following inspection of a moribund Austrian pine during an extension call (see figure 4). It looks as though they may have been a significant contributor to the mortality of the tree. This collection was made within the Nepean City Limits, Kemptville district. Ips pini is considered a common pest of pines and at times can be aggressive.
This insect was found in Rear of Young and Escott Township, Kemptville District to be causing branch mortality to an open growing ornamental birch (see figure 3).
Figure 4. Ips pini and damage on an Austrian pine in the Kemptville district within the Nepean city limits. (Aspen Zeppa, Sept. 2010)
Figure 3. Bronze birch borer larva and damage (Aspen Zeppa, Sept. 2010)
Eriophyid mite on butternut Phytoptus tristriatus Nalepa. This mite was noted in different locations across the Kemptville District to be causing indentations
Southern Kemptville, Pembroke, Algonquin Park Districts Aspen Zeppa 613-258-4072 or aspen.zeppa@ontario.ca in the underside of the leaflets of butternut (see figure 5).
Figure 6. Birch sawfly larva collected from white birch in Perth, Kemptville district. (Aspen Zeppa, Sept. 2010) Figure 5. Mite damage to the underside of Butternut leaves in Cornwall. (Aspen Zeppa, Sept 2010) More of an aesthetic pest the damage eventually looks like a black convex blotch on the upper portion of the leaflet. Confirmed in Cornwall Township, Kemptville District, the tree sustained damage to approximately 10% of the overall foliage.
Maple tar spot Rhytisma americanum Conspicuous round black fruiting bodies of the maple tar spot were observed on open growing maple foliage in South Gower Township, Kemptville District (see figure 7). Approximately 50% of the trees overall foliage was affected.
Birch Sawfly Arge pectoralis (Leach) Observations of defoliation by the birch sawfly of a 20 metre white birch were of less than 5% defoliation to the overall crown. This collection was made following an extension call in Rear of Young and Escott Township, Kemptville District (see figure 6). In large populations this insect has the ability to cause moderate to severe defoliation. Figure 7. Tar spot fruiting bodies on Norway maple. (Aspen Zeppa, Aug. 2010)
Southern Kemptville, Pembroke, Algonquin Park Districts Aspen Zeppa 613-258-4072 or aspen.zeppa@ontario.ca Tubakia leaf spot Tubakia dryina This leaf spot was found on an open growing white oak. Desiccation of the leave was visible on almost all foliage, starting from the leaf margin and working its way in (see figure 8).
Figure 8. Tubakia leaf spot on white oak, Kemptville district. (Aspen Zeppa, Aug. 2010) Damage to foliage was generally greater than 50%. This collection was made in South Gower Township, Kemptville District.
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