20 Types of Planthopper: Identification, Habitat and Lifecycle

Planthoppers are small, sap-feeding insects found worldwide, known for their unique jumping ability and often striking wing patterns. With hundreds of species across diverse ecosystems, they play both ecological and agricultural roles. Some act as serious crop pests, damaging rice, sugarcane, and banana plants, while others contribute to natural balance. This article explores 20 distinct planthopper types, highlighting their identification, habitats, behaviors, and lifecycles.

1. Brown Planthopper (Nilaparvata lugens)

Brown Planthopper

The Brown Planthopper is one of the most destructive pests of rice crops across Asia. Known for its rapid reproduction and feeding damage, it causes “hopper burn,” leading to severe yield losses. This small insect thrives in warm, humid climates and has developed resistance to many pesticides over time.

Identification

  • Size: 3–4 mm long
  • Color: Light to dark brown with translucent wings
  • Body: Slender with strong hind legs for jumping
  • Distinct feature: Prominent snout and upward-pointing wings when at rest

Habitat

Brown Planthoppers primarily inhabit flooded rice paddies, preferring warm and humid tropical regions. They are most active during the monsoon season, where standing water supports their rapid growth. They can also be found in grassy areas surrounding rice fields.

Behaviors

These insects are sap-sucking pests that feed on the phloem of rice plants. They often form dense colonies, leading to plant wilting and discoloration. Brown Planthoppers also transmit viral diseases such as the grassy stunt and ragged stunt viruses, making them doubly harmful to rice crops.

Diet

The Brown Planthopper feeds exclusively on rice sap using its piercing-sucking mouthparts. This feeding method weakens the plant, reduces grain production, and can cause entire rice patches to wither. They rely on continuous access to rice plants to survive and reproduce.

Lifecycle

Their lifecycle includes egg, nymph, and adult stages, completing in about 25–30 days under ideal conditions. Females lay eggs inside rice leaf sheaths, and nymphs hatch within a week. They undergo five nymphal stages before reaching adulthood, often overlapping generations during the growing season.

2. Green Rice Leafhopper (Nephotettix virescens)

Green Rice Leafhopper

The Green Rice Leafhopper is a common pest in rice-growing regions of Asia. Recognized for its bright green color and wedge-shaped body, it feeds on rice sap and transmits viral diseases that stunt plant growth, making it one of the key threats to rice productivity.

Identification

  • Size: Around 3–4 mm long
  • Color: Bright green with light yellow markings
  • Shape: Wedge-shaped body tapering at the end
  • Wings: Transparent and extend beyond the abdomen

Habitat

Green Rice Leafhoppers thrive in lowland rice fields, particularly where water management is poor. They prefer warm and humid climates, commonly found in tropical and subtropical regions. These pests often inhabit the undersides of rice leaves, where they feed and reproduce.

Behaviors

These leafhoppers are highly mobile and can move quickly between plants. They feed on plant sap, causing yellowing of leaves and reduced vigor in rice plants. More importantly, they transmit tungro virus, a major disease that severely damages rice crops across Asia.

Diet & Lifecycle

Green Rice Leafhoppers feed on rice plant sap using needle-like mouthparts. Their lifecycle includes egg, nymph, and adult stages, completed in about 20–25 days. Females insert eggs into leaf tissue, and nymphs undergo several molts before reaching maturity, leading to overlapping generations during crop seasons.

3. White-Backed Planthopper (Sogatella furcifera)

White-Backed Planthopper

The White-Backed Planthopper is a major rice pest known for its distinct white dorsal stripe. It causes direct damage by sucking sap from rice plants and indirectly by transmitting viral diseases. Large infestations can lead to “hopper burn,” severely reducing rice yields.

Identification

  • Size: 3–4.5 mm long
  • Color: Brownish-grey body with a distinctive white band on the back
  • Wings: Transparent and slightly longer than the body
  • Legs: Strong hind legs adapted for jumping

Habitat

This species prefers flooded rice paddies in tropical and subtropical regions. It flourishes during warm, humid seasons and often migrates long distances with the wind to locate new rice fields. Populations increase rapidly in densely planted, waterlogged environments.

Behaviors

White-Backed Planthoppers are highly social and form large colonies on the lower parts of rice stems. They weaken plants through constant feeding and can transmit the Southern rice black-streaked dwarf virus. Their movement and feeding patterns make them difficult to control once established.

Diet & Lifecycle

These planthoppers feed exclusively on rice sap using specialized piercing mouthparts. Their lifecycle includes egg, nymph, and adult stages, completed within 25–30 days. Females deposit eggs inside rice leaf sheaths, and nymphs develop through five molts before becoming adults capable of flight and reproduction.

4. Sugarcane Planthopper (Perkinsiella saccharicida)

Sugarcane Planthopper

The Sugarcane Planthopper is a major pest that infests sugarcane fields across tropical and subtropical regions. It causes significant yield loss by extracting plant sap and transmitting diseases. Its dense colonies and honeydew secretion often lead to sooty mold growth on sugarcane leaves.

Identification

  • Size: About 4–5 mm long
  • Color: Pale brown or gray with translucent wings
  • Body: Slender, with a slightly pointed head
  • Distinctive feature: Long, upward-curving wings when at rest

Habitat

This species primarily inhabits sugarcane plantations but can also be found on wild grasses nearby. It thrives in hot, humid environments and reproduces rapidly during wet seasons. Sugarcane planthoppers usually stay on the lower parts of the plant where moisture levels are high.

Behaviors

Sugarcane planthoppers feed by piercing the plant’s vascular tissues and sucking out sap, leading to reduced sugar content and plant vigor. They excrete honeydew, which promotes sooty mold growth. They also serve as vectors of the Fiji leaf gall virus, which causes gall formation on sugarcane leaves.

Diet & Lifecycle

They feed exclusively on sugarcane sap. Their lifecycle consists of eggs, nymphs, and adults, completing within 25–35 days. Females lay eggs on the underside of sugarcane leaves, and nymphs pass through five developmental stages before adulthood, often overlapping multiple generations in a single season.

5. Spotted Lanternfly (Lycorma delicatula)

Spotted Lanternfly

The Spotted Lanternfly is a striking and invasive planthopper native to Asia but now found in several parts of the world, including the United States. Its attractive wings hide a destructive nature, as it feeds on sap from a wide range of trees and crops, causing widespread agricultural damage.

Identification

  • Size: About 20–25 mm long
  • Color: Grayish forewings with black spots; hind wings red with black patches
  • Body: Stout with a bright yellow abdomen
  • Distinctive feature: Large, colorful wings visible during flight

Habitat

Spotted Lanternflies prefer forest edges, orchards, and vineyards. They commonly infest trees like the Tree of Heaven (Ailanthus altissima), grapes, and fruit trees. They thrive in temperate climates and often gather in large groups on tree trunks and branches.

Behaviors

These insects are known for their mass swarming behavior and their ability to feed on more than 70 different plant species. Their feeding weakens plants, leading to oozing wounds and mold growth. Though capable of short flights, they primarily move by jumping and are spread through human transport of infested material.

Diet & Lifecycle

Spotted Lanternflies feed on sap from trees, vines, and crops using piercing-sucking mouthparts. Their life cycle lasts about one year, with eggs laid in fall and hatching in spring. Nymphs go through four stages before maturing into adults, with peak activity observed in late summer and early autumn.

6. Glassy-Winged Planthopper (Hyalesthes obsoletus)

Glassy-Winged Planthopper

The Glassy-Winged Planthopper is a small but impactful pest, primarily known for transmitting plant diseases in vineyards and other crops. Its transparent wings and jumping ability make it easily recognizable. It’s especially problematic in Europe, where it spreads the phytoplasma causing grapevine yellows.

Identification

  • Size: 4–5 mm long
  • Color: Brownish-gray body with transparent wings
  • Wings: Clear, glass-like texture with fine venation
  • Distinctive feature: Strong jumper with short antennae

Habitat

This species thrives in dry, sunny regions, especially near vineyards and grasslands. It prefers areas with herbaceous plants like nettles and bindweed, which act as host plants. Adults are often found on plant stems, where they feed and lay eggs.

Behaviors

Glassy-Winged Planthoppers are highly active and capable of short, rapid jumps to escape predators. They feed on plant sap and are notorious for transmitting stolbur phytoplasma, a pathogen that affects several crops including grapevine, tomato, and maize.

Diet & Lifecycle

They feed on the phloem sap of various herbaceous plants. Their lifecycle spans about 6–8 weeks, with eggs laid on host plant roots. Nymphs develop underground, feeding on root sap before emerging as winged adults in late spring or early summer.

7. Rice Planthopper (Laodelphax striatellus)

Rice Planthopper

The Rice Planthopper, also known as the Small Brown Planthopper, is a significant pest of rice, wheat, and maize crops. Despite its small size, it causes massive agricultural losses due to both direct feeding damage and its role in transmitting viral diseases.

Identification

  • Size: 2.5–3.5 mm long
  • Color: Light brown to dark gray
  • Shape: Slender body with narrow wings
  • Distinctive feature: Short, triangular head and striped pattern on wings

Habitat

These planthoppers inhabit paddy fields, grasslands, and wheat-growing regions. They thrive in temperate and subtropical climates, often overwintering in grassy fields before migrating to rice paddies during the growing season.

Behaviors

Rice Planthoppers exhibit both short-winged (brachypterous) and long-winged (macropterous) forms. The long-winged adults migrate long distances, while the short-winged types reproduce rapidly in stable habitats. They transmit serious plant viruses like the rice stripe and rice black-streaked dwarf viruses.

Diet & Lifecycle

They feed exclusively on the phloem sap of rice and wheat plants. The lifecycle includes egg, five nymphal stages, and adult phases, completing in about 20–30 days. Eggs are laid inside plant tissue, and nymphs hatch within a week, maturing rapidly in warm, moist environments.

8. Coconut Planthopper (Proutista moesta)

Coconut Planthopper

The Coconut Planthopper is a notorious pest of coconut and other palm species. It weakens palms by feeding on their sap and excreting honeydew that encourages sooty mold, reducing photosynthesis. Infestations can significantly impact coconut yield and overall palm health.

Identification

  • Size: Around 5–6 mm long
  • Color: Light brown to dark brown
  • Wings: Transparent with a slight brown tint
  • Distinctive feature: Long snout and waxy filaments at the abdomen tip

Habitat

This species primarily inhabits coconut plantations and other palm-growing areas. It thrives in tropical and subtropical climates, particularly in coastal regions. They prefer dense plantations where humidity is high, favoring the undersides of palm fronds.

Behaviors

Coconut Planthoppers feed in groups, forming colonies on the undersides of palm leaves and flower stalks. They secrete honeydew that attracts ants and fosters fungal growth. These insects are poor fliers but can spread through the movement of infested planting materials.

Diet & Lifecycle

They feed exclusively on palm sap using piercing-sucking mouthparts. The lifecycle includes egg, nymph, and adult stages, lasting 30–40 days. Females lay eggs on tender fronds, and nymphs pass through five molts before reaching adulthood, overlapping multiple generations yearly.

9. Mango Planthopper (Idioscopus clypealis)

Mango Planthopper

The Mango Planthopper is a significant pest of mango trees across South and Southeast Asia. It feeds on sap from tender shoots, inflorescences, and leaves, reducing fruit set and yield. Heavy infestations lead to honeydew accumulation and sooty mold formation.

Identification

  • Size: About 4–5 mm long
  • Color: Light green or yellowish with brown markings
  • Shape: Wedge-shaped body with transparent wings
  • Distinctive feature: Prominent eyes and pointed head

Habitat

Mango Planthoppers are found in mango orchards and nearby vegetation. They thrive in warm, dry climates and are most active during the flowering season. Adults often rest on young shoots and panicles, feeding and laying eggs on soft plant tissues.

Behaviors

They are diurnal insects, actively feeding during the day. Their feeding causes sap loss and deformation of mango inflorescences. Large populations attract ants and encourage the development of sooty mold, reducing photosynthetic activity and fruit quality.

Diet & Lifecycle

These planthoppers feed primarily on mango sap, targeting flowers and young shoots. The life cycle lasts about 25–30 days, with eggs laid in leaf midribs or panicles. Nymphs develop through five instars before becoming adults, with several overlapping generations each mango season.

10. Maize Planthopper (Peregrinus maidis)

Maize Planthopper

The Maize Planthopper is a small but economically significant pest that targets maize and sorghum crops. It’s notorious for transmitting viral diseases, such as maize mosaic virus, that cause major yield losses in tropical and subtropical farming regions.

Identification

  • Size: About 3–4 mm long
  • Color: Light brown to grayish
  • Wings: Transparent and slightly elongated
  • Distinctive feature: Slender body with strong jumping legs

Habitat

This species thrives in maize, sorghum, and millet fields, especially in warm, humid areas. It prefers dense crops where it can feed and reproduce easily. Maize planthoppers are often found on the undersides of leaves and around plant stems.

Behaviors

Maize Planthoppers are strong jumpers and move easily between plants, facilitating rapid infestation. They feed on plant sap and inject toxic saliva that stunts plant growth. Their population increases quickly during the wet season, especially in fields with continuous maize cultivation.

Diet & Lifecycle

They feed exclusively on the phloem sap of maize and related grasses. Their lifecycle includes egg, five nymphal instars, and adult stages, completing within 20–25 days. Females insert eggs into leaf sheaths, and nymphs mature rapidly in favorable, moist conditions.

11. Pine Planthopper (Acanalonia conica)

Pine Planthopper

The Pine Planthopper is a unique species often seen on pine trees and shrubs. Although less destructive than agricultural planthoppers, it plays a role in forest ecosystems and can sometimes cause localized damage to ornamental conifers.

Identification

  • Size: Around 6–8 mm long
  • Color: Light green or bluish-green
  • Shape: Triangular, leaf-like body
  • Distinctive feature: Broad wings giving a flattened, angular appearance

Habitat

This planthopper is found in pine forests, gardens, and wooded areas across North America. It favors dry, sunny environments and often rests on pine needles and bark. Adults blend with foliage, making them difficult to spot.

Behaviors

Pine Planthoppers are solitary and slow-moving insects. They rely on their leaf-like camouflage to avoid predators. Though their sap-feeding can weaken young pine shoots, infestations are usually mild and do not lead to severe damage.

Diet & Lifecycle

They feed on the sap of pine and other woody plants using piercing-sucking mouthparts. Their lifecycle lasts 6–8 weeks, with eggs laid on pine twigs. Nymphs develop through five stages before reaching adulthood, often emerging in late spring to early summer.

12. Longhorned Planthopper (Dictyophara europaea)

Longhorned Planthopper

The Longhorned Planthopper is a slender and elegant insect recognized by its elongated head and antennae. Found widely across Europe and Asia, it primarily inhabits grasslands and meadows, where it feeds on a variety of herbaceous plants.

Identification

  • Size: About 8–10 mm long
  • Color: Pale green or brownish-green
  • Shape: Long, pointed head resembling a snout
  • Distinctive feature: Extended antennae and elongated wings

Habitat

This species prefers open grassy fields, forest edges, and dry meadows. It is commonly seen on wild plants such as thistles and nettles. Longhorned Planthoppers favor sunny habitats with low vegetation density.

Behaviors

They are strong jumpers and rely on camouflage to avoid predators. Though not a major agricultural pest, they play a role in the ecosystem by feeding on plant sap and serving as prey for small birds and spiders.

Diet & Lifecycle

They feed on phloem sap from grasses and wildflowers. Their lifecycle lasts 6–8 weeks, including egg, nymph, and adult stages. Eggs are laid on plant stems, and nymphs develop through five molts before maturing into adults during late summer.

13. Flatid Planthopper (Flatormenis proxima)

Flatid Planthopper

The Flatid Planthopper is a visually striking insect often mistaken for a small leaf due to its wing shape and color. It’s found throughout North America and is commonly seen in gardens, forests, and shrublands.

Identification

  • Size: 6–8 mm long
  • Color: Light green to bluish-green
  • Shape: Flattened body resembling a leaf
  • Distinctive feature: Wings held tent-like over the body

Habitat

This planthopper inhabits wooded areas, gardens, and shrublands, often resting on the undersides of leaves. It prefers humid, shaded environments and is active during warm months, especially from late spring to early autumn.

Behaviors

Flatid Planthoppers move slowly and rely heavily on camouflage for protection. They excrete a waxy substance that covers their bodies, deterring predators. While they occasionally feed on ornamental plants, they rarely cause serious damage.

Diet & Lifecycle

They feed on the sap of shrubs, trees, and vines. Their lifecycle includes egg, nymph, and adult stages, typically lasting 7–9 weeks. Females lay eggs in plant bark, and the wax-covered nymphs hatch and mature through several instars before becoming adults.

14. Bamboo Planthopper (Ricania speculum)

Bamboo Planthopper

The Bamboo Planthopper is a visually distinct insect commonly found in bamboo forests and plantations throughout Asia. Known for its glossy, patterned wings, it plays a significant role in the ecosystem but can become a pest when populations grow dense on cultivated bamboo.

Identification

  • Size: Around 8–10 mm long
  • Color: Dark brown to black with white spots
  • Wings: Broad, glossy, and patterned like glass
  • Distinctive feature: White semicircular marks on wings resembling a mirror pattern

Habitat

Bamboo Planthoppers live mainly in tropical and subtropical bamboo forests. They prefer shaded, humid environments and are usually found on the undersides of bamboo leaves and culms. Populations thrive in dense vegetation with ample moisture.

Behaviors

These planthoppers are sedentary, relying on camouflage for protection. They move short distances when disturbed, often jumping between bamboo stems. During outbreaks, they cause leaf discoloration and sap depletion, weakening young bamboo shoots.

Diet & Lifecycle

They feed primarily on bamboo sap using piercing-sucking mouthparts. The lifecycle spans 30–40 days, progressing through egg, nymph, and adult stages. Eggs are laid in bamboo tissues, and nymphs mature over several weeks, often overlapping multiple generations per year.

15. Tropical Planthopper (Euricania facialis)

Tropical Planthopper

The Tropical Planthopper is a striking species found across Southeast Asia and Oceania. With its distinctive wing pattern and preference for humid forests, it is both a fascinating insect to observe and a minor pest to fruit trees and shrubs.

Identification

  • Size: 7–9 mm long
  • Color: Dark brown or black with white or gray wing patches
  • Shape: Broad, triangular wings held roof-like over the body
  • Distinctive feature: Prominent facial ridges and spotted wings

Habitat

This species inhabits tropical rainforests, fruit orchards, and plantations. It prefers shaded, humid conditions and can often be seen resting on the undersides of leaves. They are most active during early morning and late afternoon.

Behaviors

Tropical Planthoppers move sluggishly and depend on their wing patterns for camouflage. They occasionally feed on cultivated plants such as mango, guava, and banana. When disturbed, they make short hopping movements to nearby leaves or stems.

Diet & Lifecycle

They feed on the sap of tropical trees and shrubs. Their lifecycle lasts around 35–45 days, including egg, nymph, and adult stages. Eggs are deposited in leaf veins, and nymphs develop rapidly in warm, moist conditions before becoming fully winged adults.

16. Treehopper Planthopper (Oliarus filicicola)

Treehopper Planthopper

The Treehopper Planthopper is a small, elusive species found mainly in forested regions. Despite its name, it’s more closely related to planthoppers than true treehoppers. It feeds on sap from ferns and trees, playing a minor ecological role in nutrient cycling within forest ecosystems.

Identification

  • Size: Around 5–7 mm long
  • Color: Brown or tan with mottled wings
  • Shape: Compact body with upward-angled wings
  • Distinctive feature: Slightly hump-backed thorax and short snout

Habitat

This species inhabits humid forests, especially near ferns and moss-covered trees. It prefers shaded areas with dense vegetation and high moisture levels. Treehopper Planthoppers are often found resting on the underside of fern fronds.

Behaviors

Treehopper Planthoppers are timid and tend to remain motionless when approached. They rely on camouflage and quick jumping movements for protection. Although not considered an agricultural pest, they play a role in maintaining the natural balance of forest habitats.

Diet & Lifecycle

They feed on the sap of ferns and other understory plants. Their lifecycle lasts about 30–40 days, including egg, nymph, and adult stages. Eggs are laid on plant stems, and nymphs undergo several molts before maturing into winged adults by mid-summer.

17. Melon Planthopper (Hyalesthes luteipes)

Melon Planthopper

The Melon Planthopper is a lesser-known pest affecting melons and cucurbit crops. Though not as widespread as other species, it can transmit phytoplasma diseases that cause stunting and yellowing in crops, making it an emerging concern for vegetable growers.

Identification

  • Size: 4–5 mm long
  • Color: Pale yellow to light brown
  • Wings: Transparent with faint venation
  • Distinctive feature: Small head and rounded body shape

Habitat

Melon Planthoppers are found in warm, dry agricultural regions where cucurbit crops like melons, cucumbers, and squashes are cultivated. They often inhabit the lower leaf surfaces and stems of host plants, preferring sunny and well-drained fields.

Behaviors

These insects are highly mobile and tend to move between plants quickly when disturbed. They feed in groups, causing leaf yellowing and reduced vigor in infested crops. Their potential to transmit plant pathogens makes them a growing pest concern.

Diet & Lifecycle

Melon Planthoppers feed primarily on the sap of melons and other cucurbits. Their lifecycle lasts 25–35 days, progressing through egg, five nymphal instars, and adult stages. Eggs are laid on leaf midribs, and nymphs mature quickly under warm field conditions.

18. Palm Planthopper (Lophops carinata)

Palm Planthopper

The Palm Planthopper is a common pest in tropical regions, primarily attacking palms and other monocot plants. It causes significant sap loss and fosters sooty mold growth through its honeydew excretions, reducing plant vigor and aesthetic value.

Identification

  • Size: 7–9 mm long
  • Color: Brown to reddish-brown
  • Wings: Broad and tent-like with dark veins
  • Distinctive feature: Pronounced carina (ridge) on the head and thorax

Habitat

This species inhabits palm groves, coconut plantations, and ornamental gardens. It prefers warm, moist environments and is often found on the undersides of palm fronds or around the base of fronds where new growth occurs.

Behaviors

Palm Planthoppers form colonies that feed collectively on palm sap. Their feeding leads to chlorosis, leaf drooping, and eventual plant decline. They are weak fliers but can disperse between nearby palms through jumping and wind-assisted movement.

Diet & Lifecycle

Palm Planthoppers feed primarily on the phloem sap of palms and related species. Their lifecycle spans 30–40 days, progressing from egg to nymph to adult. Females lay eggs on young palm fronds, and nymphs pass through five instars before reaching maturity.

19. Sugarcane White Planthopper (Eoeurysa flavocapitata)

Sugarcane White Planthopper

The Sugarcane White Planthopper is a lesser-known but impactful pest affecting sugarcane crops. Its persistent feeding weakens plants, while its honeydew secretion fosters fungal growth. Though small, dense populations can cause noticeable yield reductions.

Identification

  • Size: 4–5 mm long
  • Color: Pale white or cream with yellowish head
  • Wings: Transparent with faint venation
  • Distinctive feature: Compact body and bright yellow head

Habitat

This species is found in sugarcane fields, grassy lowlands, and tropical agricultural regions. It thrives in humid climates and prefers areas with thick vegetation and consistent moisture. Populations often peak during the rainy season.

Behaviors

Sugarcane White Planthoppers live in groups and feed on the lower parts of sugarcane stems. They excrete honeydew that attracts ants and promotes sooty mold. Despite their small size, they spread quickly through infested planting material.

Diet & Lifecycle

They feed exclusively on sugarcane sap using piercing-sucking mouthparts. Their lifecycle lasts 25–35 days, including egg, nymph, and adult stages. Females lay eggs on leaf sheaths, and the nymphs undergo several molts before becoming winged adults capable of reproduction.

20. Banana Planthopper (Sogatella vibix)

Banana Planthopper

The Banana Planthopper is a small but persistent pest that infests banana plants and related crops. Its feeding activity causes leaf yellowing and curling, while heavy infestations lead to reduced plant vigor and yield losses. It is common in tropical and subtropical banana-growing regions.

Identification

  • Size: 3–4 mm long
  • Color: Light brown to pale gray
  • Wings: Transparent with fine veins extending beyond the abdomen
  • Distinctive feature: Slender body with strong hind legs for jumping

Habitat

This species primarily inhabits banana plantations and grassy areas near cultivated fields. It thrives in warm, humid climates and tends to occupy the lower surfaces of banana leaves, especially in shaded, moisture-rich environments.

Behaviors

Banana Planthoppers are active during early morning and late evening. They live in colonies, feeding on banana sap and secreting honeydew that fosters sooty mold. Though weak fliers, they disperse quickly between nearby plants through hopping or wind currents.

Diet & Lifecycle

They feed exclusively on the phloem sap of banana plants and sometimes on wild grasses. The lifecycle takes about 25–30 days, including egg, five nymphal instars, and adult stages. Females deposit eggs on leaf sheaths, and multiple overlapping generations occur each year in favorable climates.