Delphastus catalinae
A tiny, shiny, dark brown to black ladybird, 1.3–1.4 mm (about 1/16 in) long, that eats all stages of whitefly but prefers eggs and young nymphs. An adult can eat up to 160 eggs a day. It is a hot-spot tool: it needs a lot of whitefly to keep breeding, so it is released onto heavy patches alongside parasitic wasps. UMass does not generally recommend it for greenhouse growers, because of the cost and because it needs more whitefly than a grower can accept. Older literature and some suppliers still call it Delphastus pusillus.
At a glance
- Mode
- Predator — adults and larvae
- Rate
- 10 per plant or 100 per hot spot, weekly
- Ships as
- Adults in a vial on filter paper
- Temp
- 72–80 °F (22–27 °C) best
- Eats
- Up to 160 eggs or 12 nymphs a day
- Setting
- Greenhouses, interiorscapes, protected crops
How it works
Adults and larvae both hunt whitefly, and both prefer eggs and young nymphs. Biobest puts an adult's intake at up to 160 eggs or 12 larvae a day, a larva's at about 1,000 eggs over its development, and a beetle's lifetime total at around 10,000 eggs or 700 larvae. The appetite is also the drawback: Buglogical says adults must keep eating whitefly eggs every day to go on laying (its page gives both at least 10 and over 200 eggs a day), so the beetle cannot hold on where whitefly is scarce. It avoids scales that a parasitoid has already used, so it does not undo a wasp program.
In laboratory work on tobacco whitefly (Legaspi and colleagues, 2008), development from egg to adult fell from about 24 days at 72 °F (22 °C) to 15 days at 86 °F (30 °C). The beetle did best at 72–79 °F (22–26 °C), and 86 °F harmed both larval development and egg-laying. At 79 °F (26 °C) the net reproductive rate was about 129 daughters per female. Biobest adds that it does not enter diapause in short days, so it stays active through the whole season. Before the genus was revised in 1994 this species was confused with D. pusillus, which is why both names still appear on product pages.
Is it established?
Watch the hot spots, not the whole crop. Biobest says the beetles are easiest to see at dusk or on cloudy days, on the undersides of the leaves.
- DAY 1Adults released at dusk onto the worst patches; they fly to young whitefly by scent
- WEEK 3First beetle larvae and pupae on the undersides of hot-spot leaves (Biobest)
- WEEKS 4–5New adults feeding on whitefly eggs
- MONTH 2All stages present in the oldest hot spots
Release & handling
Adults come in a small vial on filter paper, usually 100 per vial. Release them the day they arrive. Unlike most beneficials, they must not be refrigerated: Arbico says keep them cool and dark at 65–90 °F with about 75 % humidity and use them within 18 hours, and Buglogical says 59–68 °F for a short hold.
Release the same day
Within 18 hours (Arbico). Biobest advises releasing at the end of the day, around sundown.
Cool, not cold
59–68 °F (Buglogical) or 65–90 °F at about 75 % RH (Arbico). Do not refrigerate.
Straight onto hot spots
Release onto the most infested plants, at least 30–100 beetles per hot spot (Biobest). Only release once whitefly has been found; the beetle cannot breed without it.
Watch the sticky cards
At high beetle numbers some adults end up on sticky cards and rolls (Biobest).
Pesticide sensitivity
Biobest describes it as sensitive to a broad range of pesticides. Spreader-stickers and wetting agents can harm the beetles but have no residual effect, and soaps mostly hurt them indirectly by removing their food. In a study on organic squash (Razze and colleagues, 2016), PyGanic and M-Pede cut beetle numbers when adults were released one day after spraying, but not five days after. Check a product →
When to choose something else
Delphastus is for heavy whitefly patches in protected crops. Choose something else when:
- Whitefly is scarce or you are working preventively — the beetle needs a lot of prey to breed; start with Eretmocerus eremicus or Encarsia formosa
- You need an economical whole-crop program — UMass calls it generally not recommended for greenhouse growers because of cost and the high whitefly numbers it needs
- The crop is greenhouse tomato — UConn reports that it does not perform well there
- The house runs at 86 °F (30 °C) or more for long spells — breeding falls off (Legaspi and colleagues)
Where to buy
Suppliers listed alphabetically, not ranked. Some list the beetle as Delphastus pusillus. helpfulbugs takes no commission and does not sell insects.
- Applied Bio-nomics100 / 1,000CANADA
- Arbico Organics100 / 200 / 1,000US
- Biobest (Delphastus-System)100 / 1,000EU / UK
- Buglogical100 / 200 / 300US
Delphastus catalinae by target
Rate and timing differ by what you are releasing it against. Each page below is the program for one pest.