Cereal Pests Flashcards
What are the symptoms of wireworm damage
Ragged holes below soil level; yellowin of outer or centre leaves to complete crop loss
What are the cultural control methods for wireworm
Early ploughing and cultivations; firm seed bed; adequate nutrition and optimum pH; rolling thinned crops to encourage tillering
What chemical control options are there for wireworm
Seed Treatment - Signal 300 ES (Cypermethrin)
What are the constraints of treated seed for wireworm
Autumn use only
At what temperature do leatherjacket larvae feed?
Whenever soil temperatures at night exceed 5 degrees C.
What are the cultural control methods for leatherjackets?
Plough out grass early in June-early August to prevent egg laying; firm seed bed; adequate nutrition and optimum pH; Rolling thinned crops to encourage tillering
Which pest causes dead-heart symptoms? What does it look like?
Frit Fly - Yellowing hollow shoot
What are the symptoms of frit fly
Dead heart symptoms, excessive tillering induced in larger plants, young plants killed
When should you drill spring oats to avoid frit fly damage?
Before mid-April
What are the cultural controls for frit fly damage?
Sow spring oats before mid-April; leave a gap of 6 weeks after ploughing out grass (5 weeks if spraying off) before drilling cereals; rolling thinned crops to encourage tillering
When do wireworm adults emerge and feed?
Autumn
What pest is an issue after vining peas?
Wheat Bulb Fly
When do WBF eggs hatch and the larvae invade the shoots?
Late Jan
Are early or late drilled crops at most risk of WBF damage?
Late drilled winter crops and early drilled spring crops
Where in the UK is WBF common?
central eastern England
What are the cultural control methods of wheat bulb fly?
Avoid bare ground in July/early August, delay cultivations in high risk locations following crops such as vining peas, adjust seed rates and drilling dates in high risk situations, rolling thinned crops to encourage tillering
What seed treatment can be used for WBF?
Signal - cypermethrin
For seedtreated with Signal, what is the drilling depth?
2.5-4cm
Why does adjusting the seed rates affect the control of WBF?
The larvae move from tiller to tiller so dense crops will with inestations will be more devastating
What is the difference between yellow cereal fly and WBF?
Yellow cereal fly less serious as they do not progress from tiller to tiller
Only affected crops emeged in early October
When do yellow cereal fly eggs hatch?
Feburary
What are the characteristics of yellow cereal fly damage?
Ring marking and dead-heart
What are the chemical controls for yellow cereal fly? when are they used?
Cythrin, Hallmark Zeon and Decis for use at egg hatch
Pyretheroid sprays applied to control BYDV vectors may give incidental control by reducing egg laying
What happens to cereals with Gout fly infestations?
Swelling and then rotting of main stems and primary tillers of winter wheat, barley and triticale in December -Feb
What happens to spring sown crops that are infested with gout fly?
The ear can fail to emerge
Were do the first gen gout fly eggs pupate?
Stem
When do gout fly larvae pupate?
Feb-April
How many generations of gout fly are there per crop?
2
Where do the second gen of gout fly eggs pupate?
Upper emerged leavesof crops
Are early or late drilled crops most at risk of Gout Fly damage?
Early
When is the treatment of gout fly economically viable?
When half the plants at GS12 are found
When do you spray for gout fly?
7 days after eggs are found
What do you spray for gout fly?
pyretheroids
What are the two aphids that are vectors of BYDV?
Grain aphid and bird cherry aphid
Describe the cycle of BYDV.
Winged aphids introduce virus to newly emerged autumn cereal crops and their non-winged offspring spread the virus to neighboroughing plants
What are the symptoms of BYDV damage?
Patches of stunted yellow plants in concentric circles
What cultural factors affect the degree of risk of BYDV spreading?
Previous cropping and treatment of subbles (green bridge)
Drilling date - early drill = high risk
Location (Climate)
Temperature
How is the timing of the second generation, non-winged offspring calculated?
Accumulating daily average air temperatures above a baseline temperature of 3 degrees. Takes around 170 day degrees for the second generation to be produced.
What can be sprayed for BYDV? Give some examples of products and actives
Pyretheroids - lambda cyhalothrin (Hallmak Zeon), cypermethrin (Cythrin), Fluvalinate (Mavrik)
Name a tolerant variety of winter barley to BYDV?
KWS Amistar
Name a winter wheat variety resistant to BYDV.
Wolverine
What does resistanct variety mean in terms of BYDV?
The virus cannot reproduce in the plant
What does tolerant variety mean in terms of BYDV?
Virus still reproduces in the plan, symptoms are seen but a smaller yield reduction
Which two aphids reduce the yield of cereals by direct feeding
Grain aphid and rose-grain aphid
Under what environmental conditions is the risk of BYDV highest?
Dry, settled
What are the AHDB thresholds for BYDV spraying grain/rose grain aphids in summer?
Half tillers infested before GS61
2/3 tillers infested form GS61 to two weeks before the end of grain filling
What is sprayed in summer to protect cereals against summer aphids?
Pyretheroids - Llambda-cyhalothrin (Hallmark Zeon), Fluvalinate (Mavrik)
What product and active is used as a feeding blocker for aphids?
Flonicamid in Teppeki
How many eggs per year can a grey field slug produce?
up to 500
Name 8 risk factors of grey field slugs
Medium-heavy soil texture; loose cloddy seed beds; moist mild weather; favourable previous cropping (OSR); trashy crop residues, late sowing, thin or backwards crop, prior history of damage
What are the cultural management options for grey field slugs?
Increase seed rates, make seed beds fine, firm and consolidated. Drill deeper, monitor and set traps with chicken mash
How long are pellets effective for once applied to the soil?
4-7 days
What are the two types of slug pellet? When will one of them be revoked?
Metaldehyde - revoked 31/3/22
Ferric phosphaet
When do orange wheat blossom midges feed?
grain filling
How long do orange wheat blossom midge cocoons survive in the soil?
5 years
When do orange wheat blossom midges emerge?
From end of may
What are the cultural control methods for orange wheat blossom midge control?
Grow resistant variety - Skyfall
What are the chemical control options for orange wheat blossom midge?
Llambda-cyhalothrin (Hallmark Zeon)
What is the disclaimer for orange wheat blossom midge sprays
only 60% reduction
How are fields monitored for OWBM?
pheromone traps, yellow sticky traps
What are the spray thresholds for OWBM sprays?
Milling and seed crops = 1 midge per 6 ears at GS51-59
For feed crops - 1 midge/3 ears GS51-59
What Is the spray window for spraying OWBM between eggs laid and eggs hatching?
4 days
What minor pest can increase the lodging risk of cereals?
Saddle Gall midge
What is the max application rate of metaldehyde?
210g per crop
