Spider
Hosts
Moths and caterpillars
Description
Some spiders' eggs are laid in a cluster in silken sacs, while some species lay their egg masses covered with silks within folded leaves. Some of these sacs are attached to the mother spiders or mothers stay nearby to guard their egg sacs. Eggs usually hatch into spiderlings within three weeks. The spiderlings may remain attached to the mother for several days on some species, but for some species they are left on their own.
Spiders are not insects. They have 8 legs while insects have 6. They do not have wings whereas insects do. They have two body sections; a united head and thorax and abdomen, while insects have three; head, thorax, and abdomen.
A female can produce 200-400 eggs but only 60-80 spiderlings can hatch from these. Females can survive 2-3 months. In some species, females die after laying eggs.
All spiders are poisonous to insects but only a few species are poisonous to humans, like the Black widow and the Brown recluse.
Conservation and management
Mulching along some sections in dikes of rice paddies, in field corners, or a portion of the fields can increase the number of spiders. They can hide in the layer of mulch that serves as their alternate habitat. They can also prey on other small insects inside the mulch. Remember, that the more food the spiders can eat, the faster their population build-up will become. Cover crops are also important to provide overwintering sites of spiders’ sacs. A spider population depends on the availability of food, the habitat, and the environmental conditions. Avoid use of pesticides as much as possible, for broad-spectrum insecticides can easily kill them.
Tachinid fly
Hosts
Aphids, armyworm, beetles, bollworm, bugs, cabbage looper, cotton stainer, cutworm, grasshoppers,
hornworm, leafhoppers, mole crickets, moths, sawflies, scale insects, stem borers, stick insects.
Description
Eggs are ovate-shaped and white in color. They are found in the skin of the host insect or in leaves
near the host and are hatched when the host ingests them.
The larvae or maggots are worm-like and lack appendages like all other fly larvae. They aregreenish-white in color. They have three larval instars and then leave the hosts to pupate in thesoil. Before pupation, some mature maggots produce hard cocoons. The larval stage takes about4 days to 2 weeks depending on the climatic conditions. The newly hatched larvae enter into itshost and feed on the content before pupating into the soil. Some tachinid species are hosts' specific,
for example for a certain species; it is parasitic only on leaf rolling caterpillars, or only on sugarcanestem borer.
Pupae are oblong, yellowish and turn darkreddish as they mature.
Adults measure between 3 and 10 mm andhave very stout bristles at the tips of theirabdomens. They look very similar to the commonhousefly but are larger with stocky and soft bodies.They vary in appearance from gray black to brightly
colored, or sometimes looking like bees. Adult Tachinid flies have only 1 pair of wings. They feed on honeydews and flower pollen. Different species have varied modified sucking type mouthparts: the cutting sponging, the piercing-sucking, and lappingsponging. Adult flies are found in almost all crop habitats, either resting on foliage or feeding on
nectars and pollen. Additionally for females, they search for hosts to lay their eggs. The female adult lays her eggs near or into the larvae, or on another insect. She can lay as many as 1000-2000 eggs in her lifetime. Adults can live from 3 days to 2 months depending on the species.
Conservation
Providing sources of food like dills, parsley, clover and other herbs are the most efficient ways to conserve Trachinid flies in the agricultural ecosystems.
Trichogramma
Hosts
Trichogramma species parasitize eggs of over 200 species of moth and caterpillars. Among these are; the rice and corn stem borer, cabbageworm, tomato hornworm, Heliotis and Helicoverpa species, codling moth, cutworm, armyworm, webworm, cabbage looper, fruit worms, and sugarcane borer.
Description
Trichogramma adults are extremely small. The female adult lays her eggs on other moths' eggs. First, she examines the eggs by antennal drumming,
then drills into the eggs with her ovipositor, and lays one or more eggs inside the moth's eggs. She usually stays on or near the host eggs until all
or most of them are parasitized. When the parasitized moth's eggs turn black, the larvae parasites develop within the host eggs. The larva eats the contents of the moth's eggs. Adults emerge about 5-10 days later depending on the
temperature. Adults can live up to 14 days after emergence. Female adults can lay up to 300 eggs.
Conservation and management
Trichogramma species differ in their searching behavior, host preferences, response to environmental conditions, and suitability in biological control uses. The timing of Trichogramma releases in the field is important. Non- parasitism could be due to the use of less suitable Trichogramma strains to the host pests, environmental conditions, and untimely release of parasitoids. It is best to release of parasitoids at the beginning of a pest infestation (when moths are first seen in the field), followed by regular releases until a natural breeding population of Trichogramma is established.
An example of this approach is the corn borer control. The first release should be during the first appearance of moths and corn borers' eggs in the cornfields. Weekly releases thereafter are to ensure the Trichogramma population build-up and parasitism occurrence. The build-up of the parasitoids depends on the presence of the pest or alternative hosts and food for adults. It is important to regulary monitor pest population, egg parasitism (parasitized eggs are black in color), and the larval infestation. Trichogramma are released as pupae in parasitized host eggs. The pupae can be pasted on
cards or put in various containers. To be successful in the field, food, host eggs and shelter must be available.
Modify cropping practices by practicing crop rotation and by planting cultivars which are favorable to Trichogramma population build-up such as wild carrots, dill, golden rod, leguminous plants, and flowering vegetables. Adults feed only on nectar, pollen, and honeydew. Many of these species are found naturally occurring in agricultural and garden habitats. Many adult parasitoids and predators benefit from sources of nectar and the protection provided by refuges such as hedgerows, cover crops, and weedy borders. Avoid indiscriminate use of hazardous pesticides to ensure their presence in agricultural fields.
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