Bugs for Growers — Natural Predators

Now is the right time to use ladybugs to control aphids, mealybugs, mites, scales and thrips- Bugsforgrowers.com

Watch YouTube video about using ladybugs for the control of aphids: "

https://youtu.be/UH9jPIUEheo

 Description: Ladybird beetles are also called as ladybugs and scientifically known as Hypodamia convergens. Both larvae and adults of ladybugs are active predators of many soft bodied insects including aphids, mealy bugs, mites and scale insects. Adult ladybugs are hemispherical shaped and bright orange to red in color with 6 black spots on each wing (Fig. 1) whereas larvae have appearance like an alligator with yellow stripes and reddish dark brown color (Fig. 2).  Since adults of ladybugs are very active predators, they can move very fast after their release and find their prey in the garden. Each adult of ladybug is capable of eating over 5000 aphids whereas each larva in its life-span can eat over 400 aphids (Fig. 3).  Use of ladybugs as biological control agents in the organic gardens is a good choice because released ladybug adults can continuously reproduce and maintain their populations as long as they find their food in the garden.  For example, once ladybugs are released in the garden, they immediately start feeding on their prey.  While feeding they mate and lay up to 1,500 tiny yellow eggs on foliage. Eggs hatch within a week into blackish brown alligator like larvae, which are very mobile. After hatching, these larvae immediately start feeding on the available insect hosts in the garden.  While feeding, larvae molts 3 times before pupation.  The pupae are orange to black in color and attached to any substrate in the garden. Young adults emerge from pupae within 1-2 weeks and life cycle continues.  Ladybugs generally complete several generations in a year and they hibernate as adults during winter. [caption id="attachment_1288" align="aligncenter" width="201" caption="Fig. 1. An adult ladybug"][/caption]   [caption id="attachment_1299" align="aligncenter" width="300" caption="Fig.2. A ladybug larva was feeding on okra aphids"][/caption]   [caption id="attachment_1300" align="aligncenter" width="300" caption="Fig. 3. Red aphids feeding on underside of a tomato leaf"][/caption]  

Ladybugs are effective against following insect pests

• Aphids
• Mealy bugs
• Mites
• Scale insects
• Thrips

How ladybugs are applied in the organic garden?

Ladybugs are commercially available and they sold about 1500 adults in a bag and one such bag is enough to treat about 900 square foot area of garden. After purchasing, if it is possible, release adults immediately at dusk in watered garden near plants infested with aphids or other host insect pests. If it is not possible to release ladybugs immediately after arrival, they can be stored in the refrigerator at 38^o F (4^oC) until you are ready to release them in the garden. However, for their highest survival rate in the refrigerator, it is recommended that the bags containing lady bird beetles should be pre-conditioned upon arrival by rinsing bags under cold water and then transfer them into the refrigerator at 4^oC (38^o F).

Are ladybugs safe to use as biological control agent?

Yes, as they are not harmful to humans, children and pets.

Research Papers: Dreistadt, S.H. and Flint, M.L 1996. Melon aphid (Homoptera: Aphididae) control by inundative convergent lady beetle (Coleoptera: Coccinellidae) release on Chrysanthemum. Environmental Entomology 25:688-697. Eigenbrode, S.D., White, C., Rohde, M. and Simon, C.J. 1998. Behavior and effectiveness of adult Hippodamia convergens (Coleoptera: Coccinellidae) as a predator of Acyrthosiphon pisum (Homoptera: Aphididae) on a Wax Mutant of Pisum sativum. Environmental Entomology 27: 902-909.

Chinch bugs: one the most severe pests of turf foliage

How to identify Chinch bugs?

Chinch bugs are true bugs as they have piercing and sucking type of mouthparts i.e. long slender beak used for sucking cell sap from grass leaves. Young stages of chinch bug are called nymphs. Newly hatched nymphs are yellow in color but their color or body markings changes from yellow to reddish-black to orange-black as they molt from one stage to other stage during development. Also, with each molt nymphs more closely look like the adults. Chinch bug adults are about 1/6 inch long, and black and white in color.

Life cycle of chinch bugs:

Chinch bugs develop through three different stages: Egg, nymph and adult. These bugs over-winter as adults in protected areas such as under shrubs, in leaf litter and thick thatch layers. In the spring, the overwintering Chinch bug adults resume feeding on new turfgrass growth and at the same time start mating. After mating, females begin laying eggs. During a life span of usually 40 to 50 days, each female lay over 300 eggs on the grass leaves or stems near the ground. Under optimal environmental temperatures, eggs hatch within 7-15 days. Immediately after hatching from eggs, chinch bug nymphs start feeding on grass foliage. While feeding on grass over the period of 4 to 6 weeks, nymphs molts (shed its cuticle) 5 times, and go through 5 stages (instars) of development and become adults (6^th stage). These adults begin mating and start laying eggs from July through August. Then as stated above, after hatching from eggs, the second generation nymphs feed through October and go though different stages of growth, and become adults, which are ready for overwintering when cool temperature sets in.

Damaging stages of chinch bugs:

All six nymphal stages of chinch bugs cause damage to grass or other host plants. Adult chinch bugs also cause serious damage to grasses.

How chinch bugs cause damage to turf?

All the stages including adults of chinch bugs feed on a variety of grasses such as bentgrass, Kentucky bluegrass, perennial ryegrass, and red fescues. Both adult and nymphs of chinch bugs cause damage by sucking cell sap with their long slender beak from grass leaves.  While feeding they also inject toxins into grass leaves that causes clogging of leaf vascular system and affecting translocation of water and nutrients.  In case of severe infestation of chinch bugs, irregular brown patches of dead grass are noticed in the sunny areas of lawns.

Biological control of chinch bugs:

Natural enemies such as ants, big eyed bugs (Geocoris uliginosus), earwigs, ground beetles (see photo below), spiders, red imported fire ants (Solenopsis invicta) and wasps (Eumicrosoma benefica) help to suppress the populations of chinch bugs.  Entomopathogenic nematodes (Steinernema carpocapsae) and fungi (Metarhizium anisopliae and Beauveria bassiana) have a potential to manage chinch bugs. [caption id="attachment_257" align="alignright" width="300" caption="Ground beetles are natural enemies of chinch bugs"][/caption]

What stages of chinch bugs can be attacked by natural enemies?

Entomopathogenic nematodes can attack both adults and nymphal stages whereas entomopathogenic fungi can attack all the life stages including eggs of chinch bugs.  Also, predatory big eyed bugs can feed on all the stages of chinch bugs.

Buy Steinernema carpocapsae Nematodes

Literature:

Baxendale, F.P., A.P. Weinhold, and T.P. Riordan. 1994. Control of Buffalograss chinch bugs with Beauvaria bassiana and entomopathogenic nematodes, 1993. Nebraska insect management and insecticide efficacy reports, Dept. of Entomology Report No. 18, Univ. of Nebr., p. 43. Carstens, J.D., Baxendale, F.P., Heng-Moss, T. M. and Wright, R.J. 2008. Predation of the Chinch Bug, Blissus occiduus Barber (Hemiptera: Blissidae) by Geocoris uliginosus (Say) (Hemiptera: Lygaeidae). Journal of the Kansas Entomological Society 81: 328-338. Cherry, R. 2001.  Interrelationship of ants (Hymenoptera : Formicidae) and southern chinch bugs (Hemiptera : Lygaeidae) in Florida lawns.  Journal of Entomological Science 36: 411-415. Cherry, R. 2005. Interrelationship of big-eyed bugs (Hemiptera: Lygaeidae) and southern chinch bugs (Hemiptera : Lygaeidae) in Florida lawns. Journal of Entomological Science 40: 385-389. Samuels, R.I. and Coracini, D.L.A. 2004. Selection of Beauveria bassiana and Metarhizium anisopliae isolates for the control of Blissus antillus (Hemiptera: Lygaeidae). Scientia Agricola 61: 271-275. Samuels, R.I., Coracini, D.L.A., dos Santos, C.A.M. and Gava, C.A.T. 2002.  Infection of Blissus antillus (Hemiptera: Lygaeidae) eggs by the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana.  Biological Control 23: 269-273.

Nematodes require special care and there are several methods of applications. The process depends on how the Nematodes come when you purchase them. It is also important to know how many nematodes need to be applied to be effective (See Table 1). This post is an overview or what is required for effective use of nematodes.

What kind of equipment is used for application of entomopathogenic nematodes?

• To apply liquid (Sponge) formulated Steinernema carpocapsae or Heterorhabdtis bacteriophora nematodes on a large area (>5000 sq ft) you can use traditional Knapsack/backpack sprayers or any other sprayers with up to 300 PSI pressures that are generally used for application of chemical pesticides.
• To apply liquid formulated Steinernema carpocapsae or Heterorhabdtis bacteriophora nematodes on a small areas (<5000 sq ft) such as vegetable and ornamental gardens you can use simple watering cans (shown in photo below).
• To apply granule formulated Steinernema carpocapsae nematodes on a small (<5000 sq ft) or large area (>5000 sq ft) you can use traditional spreaders that are used for application of granular or pallet pesticides or synthetic fertilizers.

How are nematodes applied?

• As stated above, entomopathogenic nematodes that you receive in sponge as liquid formulation are thoroughly mixed in water and can be easily sprayed on grass foliage with the traditional Knapsack/backpack sprayers or watering cans.
• However, at time of spraying care should be taken that the nematodes should not be allowed to settle at the bottom of sprayer or watering can to avoid their uneven distribution.
• To avoid the settling of nematodes at the bottom of sprayer or watering can, nematode suspension should be constantly agitated.
• However, nematodes will be easily damaged, if they are agitated through excessive recirculation of spray mix or if the temperature in the tank increases beyond 86^oF.
• Nematodes can also be applied through different types of irrigation systems but pumps should have proper pressure to avoid damage to nematodes and screen sizes should be larger than 50 mesh so that nematodes will pass through them live.
• Nematodes received in granular formulation can be directly applied using traditional spreaders that are used for application of granular or pallet pesticides or synthetic fertilizers. [caption id="attachment_80" align="alignnone" width="300" caption="Watering can for application of entomopathogenic nematodes on a small area"][/caption]

When to apply nematodes

• To target any soil dwelling stages of insect pests, entomopathogenic nematodes should be applied when young larval (caterpillars)/ nymphal stages (instars) of insects are already hatched from eggs and started feeding on grass leaves or any other crops.
• Since nematodes are very sensitive to UV light, they will die within a minute or two when exposed to full sun. Therefore, nematodes should be applied early in the morning or late in the evening to avoid exposure to UV light.
• Another advantage of applying nematodes late in the evening is that caterpillars/larvae of most of the insect pests can be easily targeted because they are generally active and searching for food during night and easily found by entomopathogenic nematodes like Steinernema carpocapsae that uses sit and wait (ambush) strategy to attack its passing by host.  Since caterpillars of many insects are moving actively during night in search of food or larvae of those insects remaining at one place and continuously feeding plant roots, can easily come across to entomopathogenic nematodes like Heterorhabdits bacteriophora or other species of Heterorhabditis that uses cruising strategy to finds its host. Heterorhabditis nematodes can also find caterpillars that are hiding under thatch during day time.

What care should be taken before and after application of nematodes?

• All nematodes require proper soil moisture for their optimal movement and infectivity.
• The activity and infectivity of nematodes can be enhanced by maintaining optimum moisture levels in the soil before and after their application.
• In case of nematode application in turf, turf should be irrigated immediately after application with at least 1/2 inch of water to rinse off nematodes from the foliage and move them into the soil and thatch.
• As nematodes are very sensitive to heat and cold, their infectivity will be reduced if soil temperature is below 4^oC (39.2^oF) and above 35^oC (95.2^oF).
• Soil temperatures between 20 to 30^oC (68 to 86^oF) are considered favorable for application of majority of nematode species and their virulence. 

How many nematodes should be applied?

• For the successful control most of the soil dwelling insect pests, the optimal rate of 1 billion infective juvenile nematodes in 100 to 260 gallons of water per acreis generally recommended (Table 1). Table1. Number of nematodes required to treat different sizes [area in sqft (sq M)] of lawns.

  Nematode species	Area in sq ft (sq meter)
  	1 (0.093)	10.76 (1)	108 (10)	1076 (100)	2500 (233)	5000 (465)	10000 (930)	43560 (4047) (an acre)
  Heterorhabdtis bacteriophora	22.9 thousand	229.6 thousand	2.3 million	22.6 million	57.4 million	114.8 million	229.6 million	1.0 billion
  Heterorhabdtis indica	22.9 thousand	229.6 thousand	2.3 million	22.6 million	57.4 million	114.8 million	229.6 million	1.0 billion
  Steinernema carpocapsae	22.9 thousand	229.6 thousand	2.3 million	22.6 million	57.4 million	114.8 million	229.6 million	1.0 billion
  Steinernema feltiae	22.9 thousand	229.6 thousand	2.3 million	22.6 million	57.4 million	114.8 million	229.6 million	1.0 billion