AHDB Pest Bulletin weekly reports 2021

3rd generation cabbage root fly now laying eggs

Key points:

Pest flies

• Egg laying by second generation carrot fly will be decreasing in warmer locations
• Egg laying by third generation cabbage root flies will be underway at the warmest sites
• Bean seed flies continue to be captured in low numbers at Wellesbourne
• AHDB are supporting a network of pheromone traps to monitor swede midge. Swede midges continue to be captured at a small number of sites.

Pest aphids and whiteflies

• 7 (2) willow-carrot aphids, 27 (11) black bean aphids, 3 (1) cabbage aphids, 6 (5) peach-potato aphids, and 10 (9) potato aphids were captured in the suction trap network during the week ending 15 August. Previous week’s totals in brackets
• Aphid counts generally reflect those from the suction trap samples
• Cabbage whitefly are continuing to develop on kale plants at Wellesbourne. The plants are part of a SCEPTREplus trial on cabbage whitefly that is underway

Pest beetles

• Numbers of brassica flea beetles are still relatively high at Wellesbourne

Pest caterpillars

• Low numbers of diamondback moth are being seen on the continent. Silver Y moths are still quite abundant in Belgium and the Netherlands. A few Silver Y moths are being trapped, and also seen during the day, in the UK 
• There are no recent reports of moths being seen in brassica crops  

Egg laying by third generation cabbage root flies starting soon

Key points:

Pest flies

• Second generation carrot fly will be continuing to lay eggs in all but the coldest locations
• Egg laying by third generation cabbage root flies is likely to start soon at the warmest sites
• Bean seed flies continue to be captured in low numbers at Wellesbourne
• AHDB are supporting a network of pheromone traps to monitor swede midge. Swede midges continue to be captured in relatively high numbers at a small number of sites. 

Pest aphids and whiteflies

• 2 (2) willow-carrot aphids, 11 (39) black bean aphids, 2 (2) cabbage aphids, 5 (15) peach-potato aphids, and 9 (26) potato aphids were captured in the suction trap network during the week ending 15 August. Previous week’s totals in brackets
• Aphid counts generally reflect those from the suction trap samples
• Numbers of cabbage whitefly are continuing to increase on kale plants at Wellesbourne. The plants are part of a SCEPTREplus trial on cabbage whitefly that is now underway

Pest beetles

• Brassica flea beetles, cabbage stem weevils and pollen beetles are still present at Wellesbourne. Numbers of flea beetles trapped have been relatively high during August and this probably reflects emergence of the new generation of adults

Pest caterpillars

• Citizen science observations show that low numbers of diamondback moth are being seen on the continent. Silver Y moths are still quite abundant in Belgium and the Netherlands. A few Silver Y moths are being trapped, and also seen during the day, in the UK.  It is worth continuing to watch the web pages and your crops
• Few dimondback moths have been captured in brassica crops currently  
• The risk of new egg-laying by first generation turnip moths is now very low. The second generation does not generally pose a risk to crops
• Small white butterflies are active

Carrot fly are laying eggs now

Key points:

Pest flies

• Second generation carrot fly will be laying eggs in all but the coldest locations
• Egg laying by second generation cabbage root flies will be continuing in cooler locations. A third generation is likely to start egg-laying at the end of August at the warmest sites 
• Bean seed flies continue to be captured at Wellesbourne
• AHDB are supporting a network of pheromone traps to monitor swede midge. Swede midges have been captured in relatively high numbers at a small number of sites. 

Pest aphids and whiteflies

• 2 (12) willow-carrot aphids, 39 (49) black bean aphids, 2 (14) cabbage aphids, 15 (33) peach-potato aphids, and 26 (49) potato aphids were captured in the suction trap network during the week ending 8 August. Previous week’s totals in brackets
• Information on the pest aphids of outdoor vegetable and salad crops captured in the AHDB network of yellow water traps in potato crops is live. Aphid counts generally reflect those from the suction trap samples
• Numbers of cabbage whitefly are increasing on kale plants at Wellesbourne. The plants are part of a SCEPTREplus trial on cabbage whitefly that is now underway

Pest beetles

• Brassica flea beetles, cabbage stem weevils and pollen beetles are still present at Wellesbourne. Numbers of flea beetles trapped have been relatively high during August and this probably reflects emergence of the new generation of adults

Pest caterpillars

• Citizen science observations show that diamondback moths are being seen on the continent in low numbers. Silver Y moths are still quite abundant in Belgium and the Netherlands. A few Silver Y moths are being trapped, and also seen during the day, in the UK.  It is worth continuing to watch the web pages and your crops
• Information on captures of diamondback moth by a national network of pheromone traps is now live. Few are being captured in brassica crops currently  
• The risk of new egg-laying by first generation turnip moths is now very low. The second generation does not generally pose a risk to crops
• Small white butterflies are active