Peppers

Common Pests:

Solutions:

Overview

Pepper is one of the most welcoming of crops for pests. The leaves are smooth and non-toxic. The climate is warm and humid. People are moving through the crop daily, providing transport for those pests not blessed with wings. Even the Glasshouse provides protection from the elements and volunteering Beneficials such as Orius, Ladybugs and Lacewings. For the Grower, Pepper is also difficult as the leathery leaves do not show pest damage quickly and the density makes monitoring difficult. Pepper, like no other crop needs effective monitoring in order to manage the pest population. We urge Pepper growers outside of the Mediterranean basin to avoid the use of A. swirskii. Thrips in Pepper, while common, and frequently overwhelming, are easily controlled by using more benign and cheaper Beneficials and seldom cause actual crop damage. Using swirskii will not allow you to follow this guideline, as swirskii is extremely detrimental to Aphidoletes aphidimyza and can also disrupt P. persimilis.

Prior to Planting Out

The house should be thoroughly cleaned. Walls, floors, posts, wires etc should be washed with soap or another suitable cleaning product. Whitefly and Aphids will persist in cool greenhouses for well over 1 month without any plant material available, but they can be killed with a thorough cleanup. Before placing any plants in the house, place a “test plant” (many “test plants” actually) in the house once the heat is turned up ahead of receiving your pepper plants.

**IMPORTANT: When using any plants, like Bush Beans to supplement feeding and breeding of beneficials, you must be certain the seeds/beans are 100% clean of any pesticides, including seed coatings. Without this step the Banker turns into a “sink,” attaching and killing beneficial insects. 

The best “test” plant is a Bush Bean. They grow quickly and are very attractive to Spider Mite, Thrip and Whitefly. This will either confirm that you did a good job cleaning up, or it will show you that you have a big, rush job ahead of you. Check the bean plants daily. If they are swarmed with spider mite, carefully discard and replace with new ones. If you don’t have time for a clean-up, at least you will be prepared for the battle. The subsequent bean plants can be used as a banker plant for an initial and early release of spider mite predators; the best at this stage being Stethorus punctillum, the spider mite destroyer. If the house has a history of spider mites, they will be hiding in the ground around the posts and the walls. An introduction of Stratiolaelaps scimitus (250 mites per square meter) at each post and along the walls will help kill the overwintering spider mites. Discuss with the propagator the presence of pests. Ensure that your plants are clean because of good pest management practices and not because of a chemical insecticide. If an insecticide is used, get all of the details such as rate and date, as well as method of application.

At Planting Out

Apply Stratiolaelaps scimitus or Gaeolaelaps gillespiei (if allowed) (both will be referred to as Ss subsequently) at a rate of 50 to 250 per square meter. Skipping plants can work in clean houses, as the Ss will disperse themselves quite well. If the house has a history of Whitefly, apply Encarsia Max at a rate of 0.25 per square meter if no whitefly is detected. At one to two whitefly per yellow card per week, increase rate to 0.5 per square meter. More Bush Beans, grown in a pot, should be strategically placed throughout the Greenhouse. In the general crop 1 Bean plant should be used every 50 to 100 square meters. More plants should be used where there has been a history of Spider Mites and in the obvious locations near heating pipes, entrances and perimeter walls. Returning Spider Mites will be obvious in 1 or 2 days on the Beans, and will stay there for some time, allowing you time to react with P. persimilis or as a breeding area for Stethorus punctillum if they aren’t already finding spider mites in your crop.. The Beans will also provide you with an “early warning system” for Thrip and Whitefly. Additionally, providing alyssum, or buckwheat to supplement flowers in your crop has proven effective for feeding parasitoids, hoverflies and brown lacewings. With adequate flowers, the use of Eupeodes americanus, the aphid-eating hoverfly, can be an important addition to pepper crops. However, be sure the alyssum is free of pesticides and pesticide seed coatings to prevent killing beneficials.

At First Flower

Apply Neoseiulus fallacis at a rate of 2 mites per square meter. Fallacis is a general predator capable of feeding on all types of spider mites, whitefly eggs, thrip larvae, etc., and pollen, which will help them persist in a clean environment. The Fallacis will be effective until serious webbing develops in a hot spot, at which time they will leave the webbed area. See below; Spider Mite Strategy Overview. Apply Micromus variegatus at a rate of 0.25 adults per square meter one time, and after the first flowers have appeared. Micromus has months of longevity feeding on a combination of flowers and soft bodied pests and have proven the best early season aphid prevention. If conditions are preferable to aphids, or by the end of April, regardless, apply Aphidoletes aphidimyza at a rate of 2000 per hectare per week. The release points must be neutral, away from any known aphids (the same spot every week). Any aphid hot spots should be treated with a direct application of Aphidoletes at a rate of 1 Aa to 100 aphids. Small hot spots should be treated by releasing some adults from a tray or with Aphidoletes Max, a hanging vial that slowly releases Aphidoletes over a 1 week period. See below; Aphid Strategy Overview. Encarsia Max release rate should go to 0.5 per square meter if Whitefly are present. Any count of over 2 whitefly per week is a serious infestation and should be countered by doubling the rates to 1 per square meter. Delphastus catalinae should be applied at a rate of 0.01 per square meter every 2 weeks. The Delphastus will scout out new pest sites and has the added ability to find and eliminate any Bemisia should they find their way into the house. See below; Whitefly Strategy Overview.

Early Season

Watch for the return of the spider mites. The Bean plants will show damage very quickly. Be prepared to replace overgrown Beans. We recommend a continuous production of Bush Beans. React by applying Pp directly to the Beans. New hot spots, affecting the crop should be dealt with by pushing a Bean seed into the substrate at the site. The Bean will leaf out in a few days, and the Spider Mites will leave the Pepper plant and move onto the Bean. Apply more Pp directly to the Bean as soon as it has leafed out. The trapping bean plants will then become Pp bankers, dispersing persimilis into the main crop as control is achieved in the beans. These beans should be left as long as possible as the spider mites will often return over a long period of time. Bean leaves that have a good balance of persimilis can be pulled off the banker plants and distributed in the crop. See below; Spider Mite Strategy Overview. Whitefly should never be given a chance to develop. Rates of release for Encarsia Max should increase to 1 per square meter and the release of Delphastus should be changed to weekly, if Whitefly has established. Eggplant trapping plants should be converted to Encarsia and Delphastus bankers by concentrating releases onto the Eggplant. See below; Whitefly Strategy Overview.

Watch for Aphids entering the house. Rates of the preventative release should increase to 5000 per hectare per week, as the crop is now much larger. Hot spots should be directly attacked with releases of adult Aa, but control of the Melon aphid will only occur by prevention, as the Melon aphid reproduces and disperses faster than the biocontrols can handle. For major infestations, rates of 8000 per hectare per week should be neutrally released until the numbers are back in manageable levels.  In order to achieve effective recovery, the ratio of Aa to aphids must be in the order of 1 to 1000. All species of aphids are controlled by Aphidoletes, however under certain circumstances other biocontrols may be needed. The presence of the “Foxglove” aphid must be dealt with immediately. Foxglove Aphids can have a very negative effect on the Pepper crop. The damage goes from leaf distortion to leader damage very quickly. The presence of Aa will help and may even prevent the Foxglove, but at cooler temperatures that Foxglove aphids prefer, Aa is slower to respond. If they aren’t already cycling, the addition of both Micromus variegatus (100-1000 per acre every two to three weeks) and Anystis baccarum (0.25-2 per acre once or as needed) are effective predators of Foxglove aphid.

Thrips should be dealt with when they arrive, and their arrival will be seen on the Bean plants first. N.cucumeris can be re-applied at 100 to 200 mites per square meter either directly applied or by slow release packs will manage a thrip attack on Peppers. Anystis baccarum in addition to cucumeris offers the best thrips control. Anystis will begin to feed on cucumeris when no thrips are present, but the regular application of cucumeris is a cost-effective way to keep the more voracious Anystis in the crop. The Stratiolaelaps in the growing media will prevent any of the soil pupating Thrips from cycling. If a leaf pupating thrip establishes, such as Echinothrips, it is a very serious threat and should be dealt with by doubling the Anystis and the cucumeris rate (at least 200 per plant) and by using numerous blue sticky traps with Vanilla (or Almond) extract on them. The vanilla will attract the Thrips away from the plant, onto the cards.

Main Season

If a general spider mite infestation is occurring, apply Stethorus punctillum at a rate of 500 per hectare, every 3 weeks. The Stethorus will fly about the greenhouse and have a preventative effect. They find spider mite by smell. We frequently find Stethorus associated with newly found hot spots. See below; Spider Mite Strategy Overview. Whitefly should be under control based on the preventative releases. But the increased density of the crop should be responded to by doubling the rate of Encarsia. Delphastus catalinae will remove very large numbers of whitefly eggs and can be used to reduce outbreaks. If Bemisia are present, Delphastus should be released every two weeks at a rate of 0.1 to 1 per square meter, depending on level of infestation. The banking Eggplants can be vacuumed with a “Dustbuster” or, even better, inoculated with extra Encarsia and Delphastus. In extremely hot situations (over 30 Celsius) whitefly adults will only live for a few days (instead of months) and will not lay eggs. See below; Whitefly Strategy Overview. Aphid control should shift entirely to Aa, as all Aphidius species will now be infested with hyperparasites. Any aphid banking system should be converted to Aphidoletes by introducing Aphidoletes directly onto the bankers. Please note that we do not recommend any Aphid Banking System. See below; Aphid Strategy Overview.

Late Season

This is the most important time of the year for spider mites. What you do at this time will determine how bad the next year will be. Every effort should be made to eliminate all of the spider mites before the beginning of September. Once the day-length begins to noticeably decrease and the evening temperatures drop, the spider mites begin diapausing. In a diapause state, spider mites are more resistant to chemicals and are not as attractive to the beneficials. Rates of Encarsia should be now at a minimum of 3 per square meter, due to the density of the crop. Adding parasites beyond 6 per square meter will have very little effect, as there are just too many whitefly and the stickiness of the honeydew will begin to impair the movement of all of the parasitoids. Delphastus will continue to work at very high whitefly densities but their impact will not be quickly seen, as they will graze on the eggs and the adult whitefly will live on for months. Aphids must be in good control going into the fall as the Aphidoletes may stop cycling due to diapause. Preventative releases will still work, as they are not being asked to cycle. Aphidius can work very well in the fall, especially if they were not used in the summer, reducing the pressure of the hyperparasites. Micromus variegatus and Anystis baccarum experience no negative impact by the cooler and darker season in terms of predation and will continue in your crop until clean-out.

Spider Mite Strategy Overview

Cleanup is essential. Physical washing and Stratiolaelaps will both have extremely high returns on investment. The monitor/banker system using beans works very well. So well, that Spider Mite has become a much lower level pest in some of our houses. The use of N. fallacis was first used to prevent chronic Russet mite problems in New England on Tomatoes. We found that, not only did the Nf eliminate the Russet mite, but the growers who used it had much better spider mite control in the following season. Nf will stay in the Peppers at low or no spider mite densities, as they are true generalists and will feed on pollen, whitefly, Thrips and any other small eggs. Their Achilles heel is that they can’t tolerate webbing, like all other Amblyseius/Neoseiulus species. Phytoseiulus persimilis is still the industry standard for knocking down two-spotted spider mite infestations but Stethorus punctillum has become a standard in some Pepper houses. These small black Beetles are Spider Mite specialists. They go after all of the commercially relevant mites, finding them by smell. Introductions once the house has warmed up and some Spider Mite pressure is seen will have a significant effect. As in all Beetles, a thorough clean-up is not expected, as they tend to graze in the most productive spots, laying their eggs in the low density left overs, but, in Peppers, they are frequently the only control needed, as the delay is usually enough for us, or the persimilis to find the spot.

Whitefly Strategy Overview

Whitefly is an insidious pest. Low numbers can give the grower a false sense of security. The longevity and fecundity of the whitefly can lead to overwhelming situations very quickly. The only sure way to control whitefly is to start clean and prevent any significant buildup. Peppers in many areas are not normally affected by Whitefly, but, Growers in those areas should never drop their guard. Once again, the Bean monitors will provide you with lots of warning. Weekly releases of preventative Encarsia must be considered similar to an insurance policy. Encarsia Max will reduce the weekly cost by allowing you to use very low rates (as low as 0.25 per meter square). Encarsia Max live longer, fly farther, and are actually smarter than refrigerated Encarsia. All of Applied’s Encarsia are held above 11 degrees Celcius and are never refrigerated. Encarsia Max is guaranteed to be no older than 48 hours from harvest. Because of the high number of leaves in a Pepper crop, as compared to Tomatoes and Cucumbers, the general rate of release of all Biological Controls should be greater. The minimum release rate of Encarsia Max should be 1 per square meter, for every meter in height. Therefore the minimum release rate should start at 1 and increase to 3 per square meter as the crop grows. Using Eggplant as a trap/banker can be very effective, although, in our experience, Encarsia Max, starting clean, will be all you need. Whitefly have a very advanced sense of smell and will move onto the Eggplant in a very profound way. If Bemisia have established, the use of Delphastus will have a major impact, and, if started early, will eliminate the Bemisia before they move on to the Greenhouse whitefly. Bemisia are much harder to monitor because they don’t evenly distribute themselves the way Greenhouse whitefly does.

Aphid Strategy Overview

Aphids such as the foxglove aphid and snapdragon aphid cause severe tissue damage that must be prevented. Both of these aphids have developed evasion tactics for Aphidius, which reduces our ability to control them. Aphidoletes however, is very effective against them. The Brown Lacewing, Micromus variegatus, appears to have an affinity for the Foxglove Aphid, and therefore should be released directly in the affected areas at a rate of 1 per square meter. Work in Holland with our distributor at Rijn Plant, a major producer of Anthurium, has shown us that Aphidoletes is a much better flier and searcher than previously thought. They also have a sense of smell that has not been fully fathomed. Over a 5 year period, we were able to develop a preventative release program that prevented aphids from establishing in the house. This technique was adapted to Pepper in 2005 in B.C. The essential components of the program are; regular releases at a “neutral” location (away from known aphid hot spots) (the same spot every week) and treatment of known “hot spots” with direct releases. All species of aphid will be eliminated at a rate of 8000 per hectare per week and all species can be prevented at a rate of 4000 per hectare per week. Burning Sulphur for fungus control severely reduces Aa’s ability to work preventatively. Late in the season, as the temperature drops and the days get shorter, Anystis baccarum and Micromus variegatus should supplement the use of Aa for aphid control. While a 2022 study from the Netherlands showed that green peach aphids can be prevented in peppers using only Micromus variegatus, we believe they live longer and lay eggs less frequently in cool weather. So while prevention may be achieved, control is often achieved with higher numbers or with supplemental products.

Thrip Strategy Overview

No screen can prevent a thrip from entering your house. Thrips are a tropical pest that has adapted very well to our moderate northern climate. Waves of Thrips will invade your house when an upwind hayfield is being cut, or the outside host plants are disturbed in any way. An invasion should be dealt with severely by introducing N. cucumeris and Anystis baccarum as soon as the first thrip is seen. In areas where it is reasonable to assume that Thrips are going to be present, the presence of N. fallacis in the crop will help “hold the fort” until the traditional biological controls are present. The presence of Stratiolaelaps or Gaeolaelaps in the root zone will also prevent soil-pupating Thrips, such as the Western Flower Thrips or Onion Thrips, from cycling in your house. Healthy, fresh cucumeris will easily handle any Thrip invasion in Peppers. Thrips are also very fond of Vanilla or Almond. A drop of either/or on a cotton ball stuck on a sticky card can increase the trapping of Thrips by up to 10 times.