White Grubs and Other Bad Blueberry Bugs

Dr. Sridhar Polavarapu

Blueberry and Cranberry Research and Extension Center

Rutgers University

Chatsworth, NJ 08019

In This Presentation ….

• Seasonal lifehistory and management of above ground pests

• Pests feeding on roots

Seasonal Lifehistory and Management of Major Pests

• Pests that occur during the dormant stage

• Pre-bloom leaf and flower feeders

• Bloom-time insect pests

• Post-bloom pests on foliage and fruit

Pests During Dormant Stage • Putnam scale is the main

concern• Problem in under-pruned

fields• Superior oil (70-second

type) @ 3 gal/ac• Lime sulfur @ 5 gal/ac• Apply on warm days (>50

F) before flower buds begin to open

Pre-bloom Leaf and Flower-Feeders

• Cranberry weevil, leafrollers, and spanworms are the major pests

• ET of one larvae per 100 clusters for caterpillars

• For CW, treat if >5 weevils per bush or 20% injured flower clusters

Bloom-time Insect Pests

• Gypsymoth larvae, leafrollers, and aphids are the main concern

• Bts and Confirm 2F are the insecticide options

• Same threshold as pre-bloom

• No aphid controls during bloom

Post-bloom Pests on Foliage and Fruit

• Cranberry fruitworm, plum curculio, blueberry aphids, and blueberry maggot are the major pests

• Leafminers, and leafrollers are occassional problems

• Most insecticide applications are made during this phase

Post-bloom Pests on Foliage and FruitCranberry fruitworm

• Single generation per year

• Pheromone traps are used for monitoring

• Single insecticide application 5-7 days after the peak

• Typical timing June 1-5

Confirm 6/1&6/8

Diazinon 6/1&6/8

Confirm 5/25&6/1

Confirm 6/1

Control0

5

10

15

20

Larvae per 100 Clusters

% Damaged Clusters

Effect of timing of Confirm 2F applications onefficacy against Cranberry Fruitworm

aa

babb

b

bb

bb

CFW 2000

Post-bloom Pests on Foliage and Fruit Blueberry aphids

• A complex of several species

• Vectors of blueberry scorch and other viruses

•Species identified in NJ blueberries• Illinoia azaleae• Ericaphis spp.• Macrosiphum euphorbiae, M. rosae• Aphis spiraecola, A. gossypii• Myzus persicae

Post-bloom Pests on Foliage and Fruit

Constraints in Managing Blueberry AphidsNatural enemies

• Low tolerance because of vector status

• Use of broadspectrum insecticides leading to natural enemy destruction

• Poor coverage

Evaluation of Imidacloprid Applied as Soil Drench Against Blueberry Aphids

• Imidacloprid treatments at 0.25 and 0.5 lb A.I./acre were evaluated as soil drench

• Four replications, 3 bushes per replication

• Insecticide was applied in 1000 mL per bush on June 7

• Aphids were sampled on June 14 and 21

0

100

200

300

Control Imidacloprid 0.25 lb.ai/ac

Imidacloprid 0.5 lb.ai/ac

Total Aphids Pre-spray 6/71st Post-spray 6/142nd Post-spray 6/21

Evaluation of imidacloprid applied as soil drench

20

40

60

80

% ITa a

a

a a a

a

ab

ba

bb

a a aa

bb

Evaluation of Foliar Applications

• Imidacloprid, Thiamethoxam, and Thiacloprid were evaluated

• Four replications, four bushes per replication in a single row

• R&D sprayer, 30 gal/acre, Conejet 4VS hollowcone nozzle

• Insecticides were applied twice on June 6 and 13 and aphids sampled on June 6, 12, and 21

Evaluation of foliar application of insecticides

% IT

Total Aphids

20

40

60

80

100

200

300Pre-Spray , 6/6Post-Spray, 6/12Post-Spray, 6/21

Control Calypso

480 SC 1.5

fl.oz/ac

Calypso

480 SC 3.0

fl.oz/ac

Provado

1.6 F 3.0

fl.oz/ac

Actara 25

WDG

85.2g/ac

a

b bcc c

a

bbc c c

a

b

bcc

c

a

bbc

c c

a a a aa

a

abcbc

c

ab

Post-bloom Pests on Foliage and FruitBlueberry maggot

Overwinters in the pupal stage

Adults emerge beginning June 10

Females need 10 days to become reproductively mature

Calendar sprays begin 10 days afteradult emergence

Blueberry Maggot Management

• Quarantine pest

• Wide-window of emergence and oviposition

• Presence of wild and voluntary sources of infestation

• Research focus on monitoring and timing of insecticide applications

Blueberry Maggot Export Regulations

• CFIA promulgated new regulations in 1999

• To qualify for export, grower must participate in a BM Certification Program

• Growers are required to follow either a calendar-based or IPM-based approach for BM management

• Major constraint in IPM adoption

Red Sphere

Green Sphere

Pherocon AM trapCurrently recommended for monitoring

Blueberry Maggot Population MonitoringBlueberry Maggot Population Monitoring

Yellow boards - hue- reflectance

Spheres- shape- intensity contrast with background

Insecticide-treated Spheres for Blueberry Maggot Control

• Ammonium acetate/carbonate

• Color

• Shape

• Fruit volatiles

• Sugar

• Proteins

Root-feeding pests and their management

Root-feeding Pests - Oriental Beetle

White Grub Rastral Patterns

Asiatic Garden Beetle

Oriental BeetleMay-June Beetle

Evaluation of Imidacloprid and Insecticidal

Nematodes Against Oriental Beetle

Treatment Appl. Date Rate/acre Grubs/plant

Admire 2F 11 June 2 pints 2.1 C

Admire 2F 8 July 2 pints 2.1 C

Admire 2F 14 August 2 pints 3.8 C

Cruiser 8 July 2.0 bill 15.8 A

Cruiser 14 August 2.0 bill 9.1 B

Untreated 9.6 B

Imidacloprid for Scarab Grub Management

•Applied as a 40cm-wide band on each side of the bush•Works best against 1st instar larvae•Apply in early June to mid-July•Irrigate before and after application•Apply in the evening hours•Current blueberry registration allows only a maximum of 0.3 lb AI/acre/year for grub control•The other 0.2 lb AI/acre/year is used for foliar control of aphids

S new 3.0

S new 1.5

S new 0.75

Hb 3.0

Hb 1.5Im

id. 0.37

Imid. 0.75

Imid 1.5

Thia. 0.6

Imid 0.37+ new-S 0.75

Control

Treatment

Greenhouse Evaluation of Insecticidal Nematodes and Chloronicotinyls - 2001

0

4

8

12

# o

f G

rub

s

Root-feeding InsectsBlueberry Mealybug

•Ant-mealybug relationship

•Disrupt this relationship for control

Any Questions ?