White/lawn grub larva photo by Steven Katovich, USDA Forest Service, www.forestryimages.org.
Grubs tend to destroy the roots and stems of garden plants. The larvae are called rookworms, because rooks are said to be particularly fond of them.
DIET: Adults feed on leaves and fruit; larvae feed on pulp of fruit.
Moths whose grubs feed on stored food - especially cereals, chocolate, cocoa, dried fruit, nuts and any flour product. In fact, true white grubs may have a brown head or even a brown body. I noticed they were in soil that I heavily amended with horse manure and would freak out when I saw them. When they reach the adult stage, they munch and destroy plant foliage.
A pair of segmented legs usually is attached to each. In some larvae, a hard or distinct head may be absent or completely hidden.
The larvae of some Japanese beetles are white to brown with brown heads. Japanese Beetle Larvae Japanese beetle grubs may be light brown, white or gray. Adults are mottled grey and brown and measure 10-15mm long. They live in the soil for about three years eating plant roots.
Anal segment: Anal plate translucent white, tinted burnt ochre. Prolegs: Translucent white with burnt ochre crochets. The 3rd and 4th antennal segments are short, the head is narrow compared to the pronotum, the eyes prominent and the upper surface shiny and heavily punctured. Similar species: The larvae of several refuse-feeding species resemble each other and should be reared to confirm identity. Head – usually a dark, often hard capsule at front of body. White grubs (right) are the larval ... larvae with 3 distinct pairs of legs and an amber-colored head.
APPEARANCE: 1/4 inch long; shiny black to tan with yellowish-white lines; orange head; wings have black F-shaped bands. Thorax – three segments immediately behind the head. Key features: Oval bugs, which are variable in size (4-10mm). The tail end of the larva is often packed with soil particles, visible as a dark mass, and the body is often bend into a "C" shape (see photo, right). This time of year when you are adding amendments and turning your soil, you may notice some white fat grubs with brown heads.
HABITS: Found primarily in orchards and the edges of deciduous woods with native hawthorns, blueberry bushes or western snowberries.
compare 227 Monopis laevigella. I use to think were cutworms but they are not. I took all of them (sometimes a lot) and give them to the chickens. e.g. Adults are metallic blue-green, ½-inch beetles with bronze wing covers, while larvae are fat, white grubs with brown heads.