SCEPTREplus: Peppers and cucumbers

EAMUs secured

Authorisations secured following SCEPTREplus trials for peppers and cucumbers: 

• Mainman as an insecticide for pepper and chilli for the control of aphids

Glasshouse potato aphid

• Crop Group: Protected edibles – sweet pepper
• Target: Glasshouse potato aphid (Aulacorthum solani)
• Period: May - August 2018

Take home message

Two products lead to more than 99% control of glasshouse potato aphid during the trial. A number of safe and effective products were identified and conventional products performed particularly well.

Trial summary

This trial aimed to evaluate how effective seven plant protection products were at controlling the pest that could be incorporated into future integrated pest management strategies. The products tested were either new to the crop or new near-market products.

Key findings

• All of the conventional products significantly reduced numbers of aphids, with two reducing numbers by more than 99%.
• None of the bio-insecticides reduced aphid numbers significantly which was possibly due to high pest levels. Repeat applications of AHDB9929 did limit the population growth
• No treatments caused phytotoxic effects

Southern green shieldbug (Nezara viridula)

• Crop Group: Protected edibles – Solanaceous and cucurbit crops
• Target: Southern green shieldbug
• Period: October 2018 – March 2019

Take home message

Begin monitoring for southern green shield bugs early in the season

Consider using light traps and trap plants, as well as use of certain biological control organisms to develop a novel integrated pest management approach. However, no firm recommendations can be made on the effectiveness of these techniques against the pest.

Trial summary

The southern green shieldbug can be a significant pest of protected crops, particularly peppers. It occurs in south-east England. It has a broad host range and is able to spread quickly.

It’s important to be familiar with the pest so it can be easily recognised.

Key conclusions

At present, control options are limited. However, there is the potential to develop integrated pest management programmes based on improved monitoring, chemical, biopesticides and biological control options.

Capsids: Review of control measures

• Crops: A range of crops (Strawberry, cherry, raspberry, blackberry, apple, pear, blackcurrant, cucumber, celery, potato, tomato)
• Target: Capsid bugs
• Period: Sept 2018 – Jan 2019

Management of these pests currently relies on application of broad-spectrum insecticides. These can be effective at killing capsids, but also reduces numbers of the naturally-occurring and released natural enemies to control other pests.

This review aims to identify capsid control options that may form basis of further research including efficacy trials.

Conclusions

• Insecticides with more selective activity against sap-feeding pests, and lower impact on beneficial natural enemies (e.g. sulfoxaflor and flonicamid) have become preferred interventions for capsids in Australia and the USA
• Novel insecticides with alternative modes of action are available for testing against capsid pests
• Improved formulation of insecticides may be possible. This may be achieved by mixing with salt or enclosing them in attractant-coated microcapsules
• The entomopathogenic fungi Beauveria bassiana and Metarhizium brunneum are available as commercial formulations and should also be considered as candidates for inclusion in efficacy testing.
• Particular weeds (e.g. nettles) are assumed to be linked with capsids and control of these is recommended
• More information is needed on the role played by natural enemies
• Semiochemical-based approaches (including push-pull strategies and pheromone based monitoring traps) have been developed for capsids as part of previous AHDB-funded work and have potential for further refinement

Cucumber Pythium Root Rot

• Crop Group: Protected edibles – cucumber
• Target: Pythium root rot
• Period: August - November 2017

Take home message

One new conventional pesticide (AHDB 9958) and one biopesticide (AHDB 9967) significantly reduced disease symptoms in the trial.

One product (AHDB 9963) led to severe phytotoxicity which was linked to difficulties with calculating application rates for its use as a drench in hydroponic systems. This is likely to be a complication for other products and we recommend taking particular care with application rate calculations in this scenario.

Trial summary

Root rot of cucumber, caused by Pythium aphanidermatum, can lead to significant crop losses. It can weaken, and even kill, young plants when they are transplanted onto rockwool slabs that have been previously infested.

When temperatures are low, the build-up of the disease is often symptomless. In late summer, crops under higher temperatures can be badly affected, especially during when they are being established after planting.

Safe, effective and approved treatment options are limited and this trial is hoping to identify new products that can control oomycete pathogens. This should be of benefit to a number of crop sectors.

Conclusions

• The standard treatment, Previcur Energy, worked well and reduced the severity of the stem base lesion by 75%.
• Two test products (AHDB 9958 and AHDB 9967) significantly reduced stem base lesions compared to the untreated crops.
• Treatment AHDB9958 reduced fruit yields, but AHDB9967 did not. However, AHDB9967 did cause problems with root development.
• AHDB9963 caused severe phytotoxicity, with plants wilting. They had reduced growth, yield and poorly developed roots. This also appeared to cause the plants to be more likely to have the disease, as lesions were higher in this treatment than in the untreated control.

• Crop: Protected edibles
• Target: Glasshouse mealybug (pseudococcus viburni)
• Period: Apr-Dec 2019

Glasshouse mealybug is a pest of many protected edible crops and control in commercial production is extremely difficult. This review set out to look at control options compatible with integrated pest management strategies. 

Conclusions

Remedial control is particularly challenging due to the concealed nature of the pest, the protection given by the waxy coating that develops as they move through their lifecycle and high reproductive rates that allow rapid resurgence of populations

Monitoring and cultural management remain important. Thorough hygiene and quarantine protocols that are strictly adhered to remain an effective way of limiting spread to un-infested areas. Careful cleaning down between crops remains important in limiting the survival between crops. Though challenges arise in hydroponic and layered systems

Natural enemies which are commercially available remain the most effective means of biocontrol, but should be used as part of a control strategy

A range of on- and off-label products are available, though these often have limited or variable efficacy. There is potential to develop IPM programmes further based on relatively new biopesticidal and chemical options, but efficacy under commercial glasshouse conditions still needs to be validated

Immature stages of the lifecycle are often the most strongly affected by product applications. Monitoring of the crop to ensure targeting of the motile crawlers may help improve efficacy. Adjuvants or dewaxing agents can also help improve control, though results can be varied.