Download - Pests & Diseases of Young Orchards - Fruit and Nutsccfruitandnuts.ucanr.edu/files/239295.pdfPests & Diseases of Young Orchards. Dani Lightle. UC Orchards Systems Advisor. Glenn, Butte,

Pests & Diseases of Young Orchards

Dani LightleUC Orchards Systems AdvisorGlenn, Butte, & Tehama Counties

© M. Gomes

Insect pests of young orchards

Ken Gray Insect Image Collection

Peach twig borer - Anarsia lineatella

• Pest in almonds

• Direct pest & indirect pest

© D. Lightle 2016

Winter - hibernaculum

Life cycle

© D. Lightle 2016


Spring – shoot strikes

Life cycle

© D. Lightle 2016


© J. Eves Spring – shoot strikes

4 generations / year


Life cycle

© D. Lightle 2016

Damage to young trees

© D. Lightle 2016

Shoot monitoring

• 1st leaf trees (same year as planting)

• Scout in April

• Consider a May spray if more than 4 shoot strikes / tree

© D. Lightle 2016

Dormant monitoring

• Crotches of 1 to 3 year old wood

• No defined damage threshold• If regularly finding

hibernacula, may choose to treat

© D. Lightle 2016

Dormant monitoring

© D. Lightle 2016

Management – UC IPM Pest Management Guidelines

www.ipm.ucdavis.edu

© D. Lightle 2016

Management – UC IPM Pest Management Guidelines

© D. Lightle 2016

Flat-headed borer – Chrysobothris mali


© M

. Mor

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Bugg

uide

.net

Other borers

Walnuts Almonds

Prune limb borer – Bondia comonanaAmerican plum borer – Euzophera semifuneralis

© D. Lightle 2016

Management of tree borers

• Prevent damage by sunburn

• Almonds may require treatment • Look for frass or gum balls• Treat in 6 week intervals while problem continues• Treatment options listed in pest management guidelines

© D. Lightle 2016

Diseases of young orchards

Disease triangleHost

Pathogen Environment

© D. Lightle 2016

Pruning wound cankers – many species

• Affect almonds and walnuts

• Causal agents may include: Botryosphaeria, Phytophthora,Ceratocystis, others

• Symptoms: Gummosis (almonds), cankers (both), branch or scaffold death (both)

© D. Lightle 2016

Band canker -Botryosphaeria dothidea

Trunk and crown cankers – many species

Phytophthora cankers

© D. Lightle 2016

Water

Host

Pathogen Environment

Disease triangle – pruning wound cankers

Pruning wound

© D. Lightle 2016

Preventing canopy, trunk, and crown cankers

• Don’t prune before rain

• Avoid large cuts when unnecessary

© Glenn Moore Photography 2013

© D. Lightle 2016






• Avoid over-irrigation & over-saturated ground

• Fungicides will not “cure” infected trees © Glenn Moore Photography 2013

© D. Lightle 2016

Crown gall – Agrobacterium tumefaciens

• Caused by a bacterium

• Affects both walnuts and almonds

• Can girdle young roots or trees

© D. Lightle 2016

Preventing and treating crown gall

Prevention

• Galltrol or similar

• Avoid injuries to roots when planting

• Disinfect pruning shears & never put on ground

© D. Lightle 2016


Treatment in walnuts

• Labor intensive (1-2hrs / tree)

• Excavate roots and expose galls

© Janine Hasey

© D. Lightle 2016


Treatment in walnuts

• Labor intensive (1-2hrs / tree)

• Excavate roots and expose galls

© Janine Hasey

• Physically remove gall (hatchet, chisel, etc)

• Flame edges or treat with bacteriocide

• Leave uncovered for 1 year

© Janine Hasey

© D. Lightle 2016