Forest and Disease Report

Minnesota Department of Natural Resources, Division of Forestry 1986 FOREST PEST REPORT

BY

The Forest Insect and Disease Unit

Minnesota Department of Natural Resources

Division of Forestry

March, 1987

St. Paul, Minnesota PREFACE

The 1986 Annual Report represents a significant change in the method of reporting information. In attempt to make the document more "reader friendly1', the contents have been reorganized. Reports on individual pests now begin with a brief introduction of statewide impacts and infestation status. This information is then followed by Regional Notes. These are meant to present high1ights or pertinent information by region on the individual pests. Coverage of Special Projects will complete the document. The historical recording of phenology, survey types and results, etc. will now be in a separate appendices. In the future these appendices will be printed separately and made available on a request basis.

It is hoped that these changes will help make this report more timely, readable and useful. The Forest Pest Unit would appreciate receiving any comments on this approach. TABLE OF CONTENTS

Page Number INTRODUCTION Preface ...... ii Minnesota Forest Insect and Disease Management Program...... v Administrative Boundaries Rap ...... vi

INSECTS .Jack Pine Budworm ...... 1 Pine Tussock Moth ...... 5 Spruce Budworm ...... 6 Ye1 1owheaded Spruce Sawfly ...... 8 Larch Sawfly ...... 9 Gypsy Moth ...... 9 Forest Tent Caterpillar...... 10 Large Aspen Tortrix...... 11 Balsam Poplar Borer ...... 15 Basswood Thrips ...... 15 Basswood Leaf Skel etonizer ...... 16 Willow Leaf Beetle...... 16

DISEASES Tarspot Needlecast of Jack Pine...... 17 Needle Droop of Red Pine ...... 17 Spruce Needle Rust ...... 18 American Spruce . Raspberry Rust ...... 19 Willow Blight Complex ...... 19

iii Page Number

DISEASES (continued)

Anthractnose ...... -20 Oak Milt...... 20 Oak Dec 1i ne ...... -21

MINOR AND INCIDENTAL PESTS Diseases ...... 22 ...... 24 SPECIAL PROJECTS Risk Rating Minnesota Hardwood Forests ...... 26 White Spruce Cone Pests ...... 26 Hebeloma Arenosa ...... 29 Sturgeon Lake Red Pine Seed Production: Cone Insects and Control Recommendations ...... 30 Dutch Elm Disease Incidence and Impact in the Red River Valley ...... 30 Budworm Pheromone Trapping ...... 39 Red Pine Stunting Studies ...... 46 Jack Pine Budworm Defol iation...... 51 APPENDICES: Survey Results and Phenological Notes Spruce Budworm ...... 54 Jack Pine Budworm ...... 63 Pine Tussock Moth ...... 72 Large Aspen Tortrix ...... 75 Forest Tent Caterpillar...... 75 INTRODUCTION

There are approximately 16.5 million acres of forest land within the State of Minnesota. Over one-half of the commercial forest land within the state is publicly owned. These forests support a 2 billion dollar forest industry, which is the third largest industry within the state. The Minnesota Department of Natural Resources (MN-DNR) has been charged by the legislature with management efforts and/or support on Minnesota's state, county, and private forest lands.

Minnesota's Forest Insect and Disease Management Unit is contained within the Forest Management Section of MN-DNR Forestry Division. Fie1d activities within this division have been regionalized into six regional administrative units. The insect and disease unit consist. of a Forest Insect and Disease Supervisor, one statewide Pesticide Use coordinator, four Regional Forest Insect and Disease Specialists and five seasonal Plant Health Specialists. The four Specialists and the five seasonal Plant Health Specialists have regional responsibilities.

S. 01in Phillips Region I11 Forest Insect and Disease Supervisor Box 44, DNR Building Robert Tiplady 500 Lafayette Road Seasonal Plant Health Specialist St. Paul, MN 55155-4044 1601 Minnesota Drive, Box 648 Brainerd, MN 56401

Mike Ph