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Pest update - Week 20(2017)

(May 15th – May 21st) Compiled by: Michael Gaffney 

logo for epic project michael gaffneyThis week saw another large increase in the number of winged Aphids appearing in water traps. Both Carrot-Willow Aphids (Cavariella aegopodii) and Cabbage Aphids (Brevicoryne brassicae) have been recovered from water traps in brassica crops in Dublin and Kilkenny this week, in high numbers. Unsprayed Brassica and Carrot crops in Dublin and Kilkenny had large numbers of aphids present, with 50% of carrots at 2TL stage having aphids present. Large numbers of Cabbage aphids were present and reproducing on unsprayed brassicas in Dublin and Kilkenny. Some Macrosiphum euphorbiae (Potato Aphid) were also recovered in water traps in Dublin and Kilkenny.

First generation Cabbage root fly activity seems to be decreasing, with egg laying decreasing from 12 eggs per plant in week 19 to 6.1 in week 20 in Dublin and 5.6 eggs per plant in week 19 in Kilkenny to 0.3 eggs per plant in week 20.

Carrot root flies continue to be active in both our Dublin and Kilkenny sites. Numbers of carrot root fly caught in a newly emerging crop (2TL stage) caught this week exceed the 2 Flies/Trap/Week threshold. Growers are advised to use yellow sticky traps to monitor the situation in their own crops.

Caterpillar eggs were observed on brassica crops in Dublin and Cork.

A single silver Y moth was recovered from a pheromone trap in Kinsealy this week. To date, no diamond back moths have been observed in traps or within monitor crops. Flea beetles have been found in high numbers in both Dublin and Kilkenny causing damage on new transplants.

Fruit Pests

Spotted wing Drosophila activity has now been observed at several locations with individuals now being caught in traps within crops. Growers should be vigilant and continue to monitor crops and implement strict hygiene practices when harvesting crops. If not already doing so, growers should commence monitoring immediately.

The number of Light apple brown moth have been caught in traps in Dublin this week increased to an average of 42, increasing from the 27 caught last week. The number trapped at Kildalton this week (8.5) is similar to those caught last week (7). There are reports of tortrix leaf rolling damage in foliage, tree and ornamental crops becoming more obvious.

Beneficial Insects

Beneficial predators and parasitoids remain very abundant in crops. Growers should apply best IPM practices to preserve and maintain these populations. Several mummified aphids were observed in field vegetable crops this week.

Further Information and Samples to: Dr Michael Gaffney, Teagasc Ashtown, Ashtown, Dublin 15

T: 0871205840 E: Michael.Gaffney@Teagasc.ie Twitter: @Mick_Gaffney

Pest update - Week 19(2017)

(May 8th – May 14th) Compiled by: Michael Gaffney

logo for epic project michael gaffneyField Vegetable Pests

This week saw another increase in the number of winged Aphids appearing in water traps. Both Carrot-Willow Aphids (Cavariella aegopodii) and Cabbage Aphids (Brevicoryne brassicae) have been recovered from water traps in brassica crops in Dublin this week. A single Myzus persicae (Peach-Potato Aphid) and Macrosiphum euphorbiae (Potato Aphid) were also recovered.

Cabbage root flies have been active for the past 8 weeks and egg laying commenced 6 weeks ago in Dublin, with a large increase in egg laying in week 15. This level of egg laying has continued, with egg counts in a newly planted broccoli crop remaining increasing from 1.8 eggs per plant in Week 18 to 12 eggs per plant this week. Egg laying is now underway at Kildalton college, where approx. 6.8 eggs per plant were laid this week. Counts from our overwintered plots do not suggest that egg laying has reduced significantly in the last 3 weeks.

Carrot root flies continue to be extremely active in our overwintered plot. The prolonged dry spell has delayed emergence in newly drilled plots, although this week’s rain should ring them along.

A single silver Y moth was recovered from a pheromone trap in Kinsealy this week. To date, no diamond back moths have been observed in traps or within monitor crops. Flea beetles and brassica seed weevils continue to be active in an overwintered brassica plot and are being found in water traps.

Fruit Pests

Spotted wing Drosophila activity has now been observed at locations in Dublin and Wexford, with individuals now being caught in traps within crops. Growers should be vigilant and continue to monitor crops and implement strict hygiene practices when harvesting crops. If not already doing so, growers should commence monitoring immediately.

A sample of severe Leafhopper damage to strawberry foliage was received this week. Damage was obvious, with silver patches appearing on the leaf. It could be mistaken for early RSM or even thrip damage.

A significant number of Light apple brown moth (27) have been caught in traps in Dublin this week with some also being trapped at Kildalton (7). There are reports of leaf rolling damage in foliage and ornamental crops becoming more obvious.

Vine weevil pupae are very obvious in the soil / growth media at the moment. A useful guide to their control has been compiled by Donal Flanagan, Teagasc Nursery Stock Specialist.

A European Tarnished Plant bug (Lygus rugulipennis) was recovered this week, these capsids can cause severe leaf deformation on Viburnum and Laurel, so growers should monitor crops for any damage.

Beneficial Insects

Beneficial predators and parasitoids remain very abundant in crops. Growers should apply best IPM practices to preserve and maintain these populations.

Further Information and Samples to: Dr Michael Gaffney, Teagasc Ashtown, Ashtown, Dublin 15

T: 0871205840 E: Michael.Gaffney@Teagasc.ie Twitter: @Mick_Gaffney 

Pest update Week 17 (2017)

(April 24th – April 28th)

This week saw an increase in the number of winged Aphids appearing in water traps. Some winged Myzus persicae (Peach-Potato Aphid) were recovered from traps in Dublin, as well as Macrosiphum euphorbiae (Potato Aphid). No cabbage aphids or carrot willow aphids were found in traps.

Cabbage root flies have been active for the past 6 weeks and egg laying commenced 4 weeks ago in Dublin, with a large increase in egg laying in week 15, which has increased again in week 16 in an overwintered cabbage crop (Eggs in Week 15 34.3, increasing to 51.2 in week 16). Egg laying has commenced in a newly planted Broccoli plot in Dublin (2.1 eggs per plant). In 2016, peak first generation egg laying occurred in Dublin and Kilkenny in the third week of May. Current counts suggest that peak egg laying may be one to two weeks earlier in 2017, however this is very dependent on temperature. Active adult flies have been caught in both sticky and water traps since March in Dublin and a significant increase in adult activity in Kildalton was observed this week.

Carrot root flies have also been active with large numbers being detected in an untreated overwintered carrot plot in Dublin for the last 2 weeks. It will take a number of weeks for these flies to sexually mature and commence egg laying, however an average of 108 individuals were recorded in an untreated overwintered carrot plot in week 15, and this has fallen to an average of 62 in week 16. Females require time to mate and mature before egg laying, but a spell of good weather can increase the speed of this development. New observation plots were recently drilled and are beginning to emerge.

No silver Y moths or diamond back moths have been observed in traps or within monitor crops. Flea beetles and brassica seed weevils continue to be active in an overwintered brassica plot and are being found in water traps.

Fruit Pests

Spotted wing Drosophila activity has now been observed at 3 Dublin locations in week 17. In 2016, early season activity was not observed until Late May. This may be due to the mild spring, but most likely its due to an increase in the pest population. Growers should commence monitoring immediately.

A sharp increase in the numbers of Light apple brown moth have been caught in traps this week, (31) over previous weeks in Dublin, with some also being trapped at Kildalton (4).

Beneficial Insects

There was a noticeable increase in the number of parasitoids, both wasps and rove beetles active within crops this week. Growers should apply best IPM practices to maintain these populations.

Further Information and Samples to: Dr Michael Gaffney, Teagasc Ashtown, Ashtown, Dublin 15

T: 0871205840 E: Michael.Gaffney@Teagasc.ie Twitter: @Mick_Gaffney

Pest update - Week 16 (2017)

(April 17th – April 23rd)

Cabbage root flies have been active for the past 5 weeks and egg laying commenced 3 weeks ago in Dublin, with a large increase in egg laying observed this week. The number of eggs per plant recovered increased from an average of 3.6 per plant in week 15 to 34.3 eggs per plant this week. In 2016, peak first generation egg laying occurred in Dublin and Kilkenny in the third week of May. Current counts suggest that peak egg laying may be one to two weeks earlier in 2017, however this is very dependent on temperature. Active adult flies have been caught in both sticky and water traps since March.

Carrot root flies have also been active with large numbers being detected in an untreated overwintered carrot plot in Dublin. It will take a number of weeks for these flies to sexually mature and commence egg laying, however average numbers of 2.3, 1.75 and 2.6 flies per yellow sticky trap were observed in Dublin for weeks 12, 13 and 14. New observation plots were drilled this week and will be used to monitor for adult activity and egg laying. Females require time to mate and mature before egg laying, but a spell of good weather can increase the speed of this development.

To date no Aphid pests of concern have been caught in water traps or sticky traps or observed on crops. No silver Y moths or diamond back moths have been observed in traps or within monitor crops.

Flea beetles and brassica weevils have been active in an overwintered brassica plot and are being found in water traps. Also found were some Scaptomyza flava individuals, which is a fruit fly whose larvae can cause mining damage, particulary in brassica baby leaf products.

Fruit Pests

Spotted wing Drosophila activity has now been observed at 2 Dublin locations in week 15. In 2016, early season activity was not observed until Late May. This may be due to the mild spring, but most likely its due to an increase in the pest population. Growers should commence monitoring immediately.

Low numbers of light apple brown moth have been caught over the last fortnight, which may indicate the emergence of the first generation of this pest.

Further Information and Samples to: Dr Michael Gaffney, Teagasc Ashtown, Ashtown, Dublin 15

T: 0871205840 E: Michael.Gaffney@Teagasc.ie Twitter: @Mick_Gaffney