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 As will not allow you to follow this guideline, as As 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 at least 2 days before the planting takes place. 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. If you don’t have time for a clean-up, at least you will be prepared for the battle. 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 Hypoaspis miles (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 Hypoaspis miles or Gaeolaelaps gillespiei (if allowed) (both will be referred to as Hm subsequently) at a rate of 50 to 100 per square meter. Skipping plants can work in clean houses, as the Hm 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. 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. The Beans will also provide you with an “early warning system” for Thrip and Whitefly.
At First Flower
Apply Amblyseius cucumeris at a rate of 2 mites per square meter. A. cucumeris 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 Ac 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 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 or Aphidius matricariae (if green peach aphid) at a rate of 1 Aa or Am 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. Alternatively, Am can be established and will bank themselves in the crop. Care should be taken to not allow them to over-parasitize the site. Once 60 % parasitism is achieved, discontinue Am applications. 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.
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. Hot Spots should have Am applied to them directly. Am should be discontinued once parasitism is more than 60%. In order to achieve effective recovery, the ratio of Aa or Am to aphids must be in the order of 1 to 1000. All species of aphids are controlled by Aphidoletes. Aphidius matricariae will easily control and cycle with Green Peach Aphid. 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, especially if the Green Peach Aphid is being well managed. It is believed that Aa prefers the Green Peach because of the higher levels of Honeydew produced. Foxglove Aphids tend to be territorial and dispersion is relatively slow, so a focused response can be very effective. Directly release Aa into the Foxglove site at a rate of 5 per square meter, every two weeks until controlled. If allowed, also release Micromus variegatus, the Brown Lacewing at 1 per square meter, also every two weeks. Thrips should be dealt with when they arrive, and their arrival will be seen on the Bean plants first. A.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. After the middle of March, Orius may be introduced at the recommended rate. The Hm 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 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.
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.
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.
Spider Mite Strategy Overview
Cleanup is essential. Physical spraying and Hypoaspis 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 A fallacis was first used to prevent chronic Russet mite problems in New England on Tomatoes. We found that, not only did the Af eliminate the Russet mite, but the growers who used it had much better spider mite control in the following season. Af 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 species. A few years ago we substituted A. cucumeris for Af in a crop that was under more Thrip pressure. We found that Ac was almost as good as Af with Spider Mites and was considerably better with Thrip, not to mention being considerably less expensive. This strategy has become our standard, due to the success of the Bean system in reducing the impact of Spider Mites. P. persimilis is still the cornerstone of Spider Mite management. We always recommend that Pp be purchased on Bean leaves, as Persimilis Max. 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, parasitoids are at a disadvantage because they are all reared on Greenhouse whitefly and parasitoids always work best on their established host. All parasitoids will adapt to Bemisia and will all host feed aggressively. The use of Delphastus will have a major impact on Bemisia, 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 5year 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, Aphidius matricariae will work well because as it is not sensitive to day length and not as sensitive as Aphidoletes with respect to temperature. When using Am, care should be taken not to over apply them. They are very efficient and can over-run the Aphid population, resulting in a crash that subsequently forces you to start all over again, which is costly and inefficient. We recommend that if Am has parasitized over 40% of the Aphids to reduce the introductions. If over 60% are parasitized, immediately stop further Am releases until the numbers drop below 50%. Applied does not recommend the aphid banking system because of its’ cost, the development of hyperparasites during the spring and summer, and the “false” targets that they present for the preventative Aphidoletes program.
Thrip Strategy Overview
No screen can prevent a thrip from entering your house. I have witnessed a thrip squeezing through the channeling on the wall of a glass house and emerging on the other side. 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 A. cucumeris 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 A. fallacis in the crop will help “hold the fort” until the traditional biological controls are present. The presence of Hypoaspis in the root zone will also prevent soil-pupating Thrips, such as WFT, 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. In our persimilis rearing system, when Onion Thrips show up in the summer, we can remove the adults by adding a drop of Vanilla to a “bug zapper”, which also attracts Thrips by the UV.